Merge branch 'master' of https://github.com/pshaughn/servo

80 files changed, 1681 insertions, 138 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0947f0385e9..a501e46e194 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -126,12 +126,33 @@ dependencies = [
 ]
 
 [[package]]
+name = "arrayvec"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cff77d8686867eceff3105329d4698d96c2391c176d5d03adc90c7389162b5b8"
+
+[[package]]
 name = "ascii"
 version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3ae7d751998c189c1d4468cf0a39bb2eae052a9c58d50ebb3b9591ee3813ad50"
 
 [[package]]
+name = "ash"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "003d1fb2eb12eb06d4a03dbe02eea67a9fac910fa97932ab9e3a75b96a1ea5e5"
+dependencies = [
+ "shared_library",
+]
+
+[[package]]
+name = "atom"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c86699c3f02778ec07158376991c8f783dd1f2f95c579ffaf0738dc984b2fe2"
+
+[[package]]
 name = "atomic_refcell"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -672,6 +693,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a475fc4af42d83d28adf72968d9bcfaf035a1a9381642d8e85d8a04957767b0d"
 
 [[package]]
+name = "colorful"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bca1619ff57dd7a56b58a8e25ef4199f123e78e503fe1653410350a1b98ae65"
+
+[[package]]
 name = "combine"
 version = "3.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -754,6 +781,7 @@ dependencies = [
  "servo_remutex",
  "servo_url",
  "style_traits",
+ "webgpu",
  "webrender_api",
  "webvr_traits",
  "webxr-api",
@@ -783,6 +811,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "copyless"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ff9c56c9fb2a49c05ef0e431485a22400af20d33226dc0764d891d09e724127"
+
+[[package]]
 name = "core-foundation"
 version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -866,7 +900,7 @@ version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fedcd6772e37f3da2a9af9bf12ebe046c0dfe657992377b4df982a2b54cd37a9"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.4.6",
  "cfg-if",
  "crossbeam-utils",
  "lazy_static",
@@ -942,6 +976,17 @@ dependencies = [
 ]
 
 [[package]]
+name = "d3d12"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc7ed48e89905e5e146bcc1951cc3facb9e44aea9adf5dc01078cda1bd24b662"
+dependencies = [
+ "bitflags",
+ "libloading",
+ "winapi",
+]
+
+[[package]]
 name = "darling"
 version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1497,6 +1542,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "gcc"
+version = "0.3.55"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f5f3913fa0bfe7ee1fd8248b6b9f42a5af4b9d65ec2dd2c3c26132b950ecfc2"
+
+[[package]]
 name = "generic-array"
 version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1566,6 +1617,123 @@ dependencies = [
 ]
 
 [[package]]
+name = "gfx-auxil"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "572eee952a9a23c99cfe3e4fd95d277784058a89ac3c77ff6fa3d80a4e321919"
+dependencies = [
+ "fxhash",
+ "gfx-hal",
+ "spirv_cross",
+]
+
+[[package]]
+name = "gfx-backend-dx11"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c66c77836ff26cf9916e5c8745715a22eae1fc61d994ffa0bea8a7dbd708ece2"
+dependencies = [
+ "bitflags",
+ "gfx-auxil",
+ "gfx-hal",
+ "libloading",
+ "log",
+ "parking_lot",
+ "range-alloc",
+ "raw-window-handle",
+ "smallvec",
+ "spirv_cross",
+ "winapi",
+ "wio",
+]
+
+[[package]]
+name = "gfx-backend-dx12"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6e913cc800fb12eaba2c420091a02aca9aafbefd672600dfc5b52654343d341"
+dependencies = [
+ "bitflags",
+ "d3d12",
+ "gfx-auxil",
+ "gfx-hal",
+ "log",
+ "range-alloc",
+ "raw-window-handle",
+ "smallvec",
+ "spirv_cross",
+ "winapi",
+]
+
+[[package]]
+name = "gfx-backend-empty"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d383e6bc48867cb37d298a20139fd1eec298f8f6d594690cd1c50ef25470cc7"
+dependencies = [
+ "gfx-hal",
+ "raw-window-handle",
+]
+
+[[package]]
+name = "gfx-backend-metal"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8de5c71f18ba805c95b84d6c78c472ef44485a6fc46e3b49fe1e6739c8d7b0c0"
+dependencies = [
+ "arrayvec 0.5.1",
+ "bitflags",
+ "block",
+ "cocoa 0.19.1",
+ "copyless",
+ "core-graphics",
+ "foreign-types",
+ "gfx-auxil",
+ "gfx-hal",
+ "lazy_static",
+ "log",
+ "metal",
+ "objc",
+ "parking_lot",
+ "range-alloc",
+ "raw-window-handle",
+ "smallvec",
+ "spirv_cross",
+ "storage-map",
+]
+
+[[package]]
+name = "gfx-backend-vulkan"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62538fedd66a78968a162e8e1a29d085ffbc97f8782634684b2f7da7aea59207"
+dependencies = [
+ "arrayvec 0.5.1",
+ "ash",
+ "byteorder",
+ "core-graphics",
+ "gfx-hal",
+ "lazy_static",
+ "log",
+ "objc",
+ "raw-window-handle",
+ "smallvec",
+ "winapi",
+ "x11",
+]
+
+[[package]]
+name = "gfx-hal"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c88981665c780447bb08eb099e1ded330754a7246719bab927ee4a949c0ba7f"
+dependencies = [
+ "bitflags",
+ "raw-window-handle",
+ "smallvec",
+]
+
+[[package]]
 name = "gfx_traits"
 version = "0.0.1"
 dependencies = [
@@ -2131,6 +2299,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
 
 [[package]]
+name = "hibitset"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47e7292fd9f7fe89fa35c98048f2d0a69b79ed243604234d18f6f8a1aa6f408d"
+dependencies = [
+ "atom",
+]
+
+[[package]]
 name = "histogram"
 version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2293,7 +2470,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7371aa3c98fad60de2d9b517e2e1ed45593c32b0c77249310fa507749a2a318b"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.4.6",
  "byteorder",
  "num-traits",
 ]
@@ -2517,17 +2694,21 @@ dependencies = [
  "cssparser",
  "euclid",
  "gfx",
+ "gfx_traits",
  "ipc-channel",
  "libc",
  "msg",
+ "range",
  "rayon",
  "rayon_croissant",
  "script_layout_interface",
  "script_traits",
  "serde",
  "servo_arc",
+ "servo_geometry",
  "style",
  "style_traits",
+ "unicode-script",
  "webrender_api",
 ]
 
@@ -2764,6 +2945,7 @@ dependencies = [
  "style_traits",
  "surfman",
  "webdriver_server",
+ "webgpu",
  "webrender",
  "webrender_api",
  "webrender_traits",
@@ -2833,7 +3015,7 @@ version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69589b8844c0b3745cc031a35b62bc33b0fb9e5ba7613756d802c52861dcdb4c"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.4.6",
  "euclid",
  "num-traits",
 ]
@@ -2989,6 +3171,21 @@ dependencies = [
 ]
 
 [[package]]
+name = "metal"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddf8052f20601c7af6293d3f7bf7b9159aee5974804fe65d871d437f933ec1eb"
+dependencies = [
+ "bitflags",
+ "block",
+ "cocoa 0.19.1",
+ "core-graphics",
+ "foreign-types",
+ "log",
+ "objc",
+]
+
+[[package]]
 name = "metrics"
 version = "0.0.1"
 dependencies = [
@@ -3393,6 +3590,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "31d20fd2b37e07cf5125be68357b588672e8cefe9a96f8c17a9d46053b3e590d"
 dependencies = [
  "malloc_buf",
+ "objc_exception",
 ]
 
 [[package]]
@@ -3407,6 +3605,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "objc_exception"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "098cd29a2fa3c230d3463ae069cecccc3fdfd64c0d2496ab5b96f82dab6a00dc"
+dependencies = [
+ "gcc",
+]
+
+[[package]]
 name = "objc_id"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -3893,6 +4100,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "range-alloc"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd5927936723a9e8b715d37d7e4b390455087c4bdf25b9f702309460577b14f9"
+
+[[package]]
 name = "raqote"
 version = "0.7.4-alpha.0"
 source = "git+https://github.com/jrmuizel/raqote#2a801bca7253e053767ef5ea11b0ee77c52617c9"
@@ -3906,6 +4119,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "raw-window-handle"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9db80d08d3ed847ce4fb3def46de0af4bfb6155bd09bd6eaf28b5ac72541c1f1"
+dependencies = [
+ "libc",
+]
+
+[[package]]
 name = "rayon"
 version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -3989,6 +4211,16 @@ dependencies = [
 ]
 
 [[package]]
+name = "relevant"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbc232e13d37f4547f5b9b42a5efc380cabe5dbc1807f8b893580640b2ab0308"
+dependencies = [
+ "cfg-if",
+ "log",
+]
+
+[[package]]
 name = "remove_dir_all"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -3998,6 +4230,33 @@ dependencies = [
 ]
 
 [[package]]
+name = "rendy-descriptor"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f475bcc0505946e998590f1f0545c52ef4b559174a1b353a7ce6638def8b621e"
+dependencies = [
+ "gfx-hal",
+ "log",
+ "relevant",
+ "smallvec",
+]
+
+[[package]]
+name = "rendy-memory"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed492161a819feae7f27f418bb16035276ac20649c60d756699152cb5c1960ec"
+dependencies = [
+ "colorful",
+ "gfx-hal",
+ "hibitset",
+ "log",
+ "relevant",
+ "slab",
+ "smallvec",
+]
+
+[[package]]
 name = "rle-decode-fast"
 version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -4077,7 +4336,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b8eb11f5b0a98c8eca2fb1483f42646d8c340e83e46ab416f8a063a0fd0eeb20"
 dependencies = [
  "approx",
- "arrayvec",
+ "arrayvec 0.4.6",
  "ordered-float",
  "stb_truetype",
 ]
@@ -4199,6 +4458,7 @@ dependencies = [
  "utf-8",
  "uuid",
  "webdriver",
+ "webgpu",
  "webrender_api",
  "webvr_traits",
  "webxr-api",
@@ -4291,6 +4551,7 @@ dependencies = [
  "time",
  "url",
  "webdriver",
+ "webgpu",
  "webrender_api",
  "webvr_traits",
  "webxr-api",
@@ -4905,6 +5166,14 @@ dependencies = [
 ]
 
 [[package]]
+name = "spirv_cross"
+version = "0.16.0"
+source = "git+https://github.com/kvark/spirv_cross?branch=wgpu#636677bad724797789239c16e6d332e9b4d97b86"
+dependencies = [
+ "cc",
+]
+
+[[package]]
 name = "stable_deref_trait"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -4927,6 +5196,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "storage-map"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd0a4829a5c591dc24a944a736d6b1e4053e51339a79fd5d4702c4c999a9c45e"
+dependencies = [
+ "lock_api",
+]
+
+[[package]]
 name = "string"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -4971,7 +5249,7 @@ name = "style"
 version = "0.0.1"
 dependencies = [
  "app_units",
- "arrayvec",
+ "arrayvec 0.4.6",
  "atomic_refcell",
  "bindgen",
  "bitflags",
@@ -5583,7 +5861,7 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2606e9192f308ddc4f0b3c5d1bf3400e28a70fff956e9d9f46d23b094746d9f"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.4.6",
 ]
 
 [[package]]
@@ -5897,6 +6175,19 @@ dependencies = [
 ]
 
 [[package]]
+name = "webgpu"
+version = "0.0.1"
+dependencies = [
+ "embedder_traits",
+ "ipc-channel",
+ "log",
+ "malloc_size_of",
+ "serde",
+ "servo_config",
+ "wgpu-native",
+]
+
+[[package]]
 name = "webrender"
 version = "0.60.0"
 source = "git+https://github.com/servo/webrender#4f2d78adb6e07e3e5ab2da9765613ecf9e07eee0"
@@ -6038,6 +6329,30 @@ dependencies = [
 ]
 
 [[package]]
+name = "wgpu-native"
+version = "0.4.0"
+source = "git+https://github.com/zakorgy/wgpu?branch=v0.4#128a16b9887a60a087a9d41ff68b20ce07cf6265"
+dependencies = [
+ "arrayvec 0.5.1",
+ "bitflags",
+ "copyless",
+ "fxhash",
+ "gfx-backend-dx11",
+ "gfx-backend-dx12",
+ "gfx-backend-empty",
+ "gfx-backend-metal",
+ "gfx-backend-vulkan",
+ "gfx-hal",
+ "log",
+ "parking_lot",
+ "rendy-descriptor",
+ "rendy-memory",
+ "serde",
+ "smallvec",
+ "vec_map",
+]
+
+[[package]]
 name = "which"
 version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index ee35ba935a9..3bb824b3417 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,3 +29,5 @@ opt-level = 3
 mio = { git = "https://github.com/servo/mio.git", branch = "servo" }
 # https://github.com/retep998/winapi-rs/pull/816
 winapi = { git = "https://github.com/servo/winapi-rs", branch = "patch-1" }
+spirv_cross = { git = "https://github.com/kvark/spirv_cross", branch = "wgpu" }
+wgpu-native = { git = "https://github.com/zakorgy/wgpu", branch = "v0.4" }
diff --git a/components/config/opts.rs b/components/config/opts.rs
index 292d06c67dc..fb4e3112837 100644
--- a/components/config/opts.rs
+++ b/components/config/opts.rs
@@ -713,6 +713,12 @@ pub fn from_cmdline_args(mut opts: Options, args: &[String]) -> ArgumentParsingR
         "A preference to set to enable",
         "dom.bluetooth.enabled",
     );
+    opts.optmulti(
+        "",
+        "pref",
+        "A preference to set to enable",
+        "dom.webgpu.enabled",
+    );
     opts.optflag("b", "no-native-titlebar", "Do not use native titlebar");
     opts.optflag("w", "webrender", "Use webrender backend");
     opts.optopt("G", "graphics", "Select graphics backend (gl or es2)", "gl");
diff --git a/components/config/prefs.rs b/components/config/prefs.rs
index 7e4fb7551a5..a1e8f96b906 100644
--- a/components/config/prefs.rs
+++ b/components/config/prefs.rs
@@ -159,6 +159,9 @@ mod gen {
                 },
             },
             dom: {
+                webgpu: {
+                    enabled: bool,
+                },
                 bluetooth: {
                     enabled: bool,
                     testing: {
diff --git a/components/constellation/Cargo.toml b/components/constellation/Cargo.toml
index ec360006aad..893930c701a 100644
--- a/components/constellation/Cargo.toml
+++ b/components/constellation/Cargo.toml
@@ -47,6 +47,7 @@ servo_geometry = {path = "../geometry"}
 servo_rand = {path = "../rand"}
 servo_remutex = {path = "../remutex"}
 servo_url = {path = "../url"}
+webgpu = {path = "../webgpu"}
 webvr_traits = {path = "../webvr_traits"}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
 webxr-api = {git = "https://github.com/servo/webxr", features = ["ipc"]}
diff --git a/components/constellation/constellation.rs b/components/constellation/constellation.rs
index 82b99938f3b..3bd77ebf137 100644
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@@ -172,6 +172,7 @@ use std::sync::Arc;
 use std::thread;
 use style_traits::viewport::ViewportConstraints;
 use style_traits::CSSPixel;
+use webgpu::WebGPU;
 use webvr_traits::{WebVREvent, WebVRMsg};
 
 type PendingApprovalNavigations = HashMap<PipelineId, (LoadData, HistoryEntryReplacement)>;
@@ -440,6 +441,10 @@ pub struct Constellation<Message, LTF, STF> {
     /// Entry point to create and get channels to a WebGLThread.
     webgl_threads: Option<WebGLThreads>,
 
+    /// An IPC channel for the constellation to send messages to the
+    /// WebGPU threads.
+    webgpu: Option<WebGPU>,
+
     /// A channel through which messages can be sent to the webvr thread.
     webvr_chan: Option<IpcSender<WebVRMsg>>,
 
@@ -521,6 +526,9 @@ pub struct InitialConstellationState {
     /// Entry point to create and get channels to a WebGLThread.
     pub webgl_threads: Option<WebGLThreads>,
 
+    /// A channel to the WebGPU threads.
+    pub webgpu: Option<WebGPU>,
+
     /// A channel to the webgl thread.
     pub webvr_chan: Option<IpcSender<WebVRMsg>>,
 
@@ -836,6 +844,7 @@ where
                         (rng, prob)
                     }),
                     webgl_threads: state.webgl_threads,
+                    webgpu: state.webgpu,
                     webvr_chan: state.webvr_chan,
                     webxr_registry: state.webxr_registry,
                     canvas_chan: CanvasPaintThread::start(),
@@ -1090,6 +1099,7 @@ where
                 .webgl_threads
                 .as_ref()
                 .map(|threads| threads.pipeline()),
+            webgpu: self.webgpu.clone(),
             webvr_chan: self.webvr_chan.clone(),
             webxr_registry: self.webxr_registry.clone(),
             player_context: self.player_context.clone(),
@@ -2355,6 +2365,17 @@ where
             }
         }
 
+        if let Some(webgpu) = self.webgpu.as_ref() {
+            debug!("Exiting WebGPU thread.");
+            let (sender, receiver) = ipc::channel().expect("Failed to create IPC channel!");
+            if let Err(e) = webgpu.exit(sender) {
+                warn!("Exit WebGPU Thread failed ({})", e);
+            }
+            if let Err(e) = receiver.recv() {
+                warn!("Failed to receive exit response from WebGPU ({})", e);
+            }
+        }
+
         if let Some(chan) = self.webvr_chan.as_ref() {
             debug!("Exiting WebVR thread.");
             if let Err(e) = chan.send(WebVRMsg::Exit) {
diff --git a/components/constellation/pipeline.rs b/components/constellation/pipeline.rs
index 3ac5ded15ed..fd7202aa9ec 100644
--- a/components/constellation/pipeline.rs
+++ b/components/constellation/pipeline.rs
@@ -46,6 +46,7 @@ use std::process;
 use std::rc::Rc;
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
+use webgpu::WebGPU;
 use webvr_traits::WebVRMsg;
 
 /// A `Pipeline` is the constellation's view of a `Document`. Each pipeline has an
@@ -188,6 +189,9 @@ pub struct InitialPipelineState {
     /// A channel to the WebGL thread.
     pub webgl_chan: Option<WebGLPipeline>,
 
+    /// A channel to the WebGPU threads.
+    pub webgpu: Option<WebGPU>,
+
     /// A channel to the webvr thread.
     pub webvr_chan: Option<IpcSender<WebVRMsg>>,
 
@@ -299,6 +303,7 @@ impl Pipeline {
                     webrender_document: state.webrender_document,
                     webgl_chan: state.webgl_chan,
                     webvr_chan: state.webvr_chan,
+                    webgpu: state.webgpu,
                     webxr_registry: state.webxr_registry,
                     player_context: state.player_context,
                 };
@@ -504,6 +509,7 @@ pub struct UnprivilegedPipelineContent {
     webrender_api_sender: webrender_api::RenderApiSender,
     webrender_document: webrender_api::DocumentId,
     webgl_chan: Option<WebGLPipeline>,
+    webgpu: Option<WebGPU>,
     webvr_chan: Option<IpcSender<WebVRMsg>>,
     webxr_registry: webxr_api::Registry,
     player_context: WindowGLContext,
@@ -556,6 +562,7 @@ impl UnprivilegedPipelineContent {
                 pipeline_namespace_id: self.pipeline_namespace_id,
                 content_process_shutdown_chan: content_process_shutdown_chan,
                 webgl_chan: self.webgl_chan,
+                webgpu: self.webgpu,
                 webvr_chan: self.webvr_chan,
                 webxr_registry: self.webxr_registry,
                 webrender_document: self.webrender_document,
diff --git a/components/gfx/text/glyph.rs b/components/gfx/text/glyph.rs
index 52faf0c5480..7492064e3f7 100644
--- a/components/gfx/text/glyph.rs
+++ b/components/gfx/text/glyph.rs
@@ -453,6 +453,11 @@ impl<'a> GlyphStore {
     }
 
     #[inline]
+    pub fn total_advance(&self) -> Au {
+        self.total_advance
+    }
+
+    #[inline]
     pub fn len(&self) -> ByteIndex {
         ByteIndex(self.entry_buffer.len() as isize)
     }
diff --git a/components/layout_2020/Cargo.toml b/components/layout_2020/Cargo.toml
index 69b0bea014e..f7167b638d5 100644
--- a/components/layout_2020/Cargo.toml
+++ b/components/layout_2020/Cargo.toml
@@ -18,15 +18,19 @@ atomic_refcell = "0.1"
 cssparser = "0.27"
 euclid = "0.20"
 gfx = {path = "../gfx"}
+gfx_traits = {path = "../gfx_traits"}
 ipc-channel = "0.12"
 libc = "0.2"
 msg = {path = "../msg"}
+range = {path = "../range"}
 rayon = "1"
 rayon_croissant = "0.1.1"
 script_layout_interface = {path = "../script_layout_interface"}
 script_traits = {path = "../script_traits"}
 serde = "1.0"
 servo_arc = { path = "../servo_arc" }
+servo_geometry = {path = "../geometry"}
 style = {path = "../style", features = ["servo", "servo-layout-2020"]}
 style_traits = {path = "../style_traits"}
+unicode-script = {version = "0.3", features = ["harfbuzz"]}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
diff --git a/components/layout_2020/context.rs b/components/layout_2020/context.rs
index 0e96797f4d7..5bde114ca57 100644
--- a/components/layout_2020/context.rs
+++ b/components/layout_2020/context.rs
@@ -3,7 +3,9 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use gfx::font_cache_thread::FontCacheThread;
+use gfx::font_context::FontContext;
 use msg::constellation_msg::PipelineId;
+use std::cell::{RefCell, RefMut};
 use std::sync::Mutex;
 use style::context::SharedStyleContext;
 
@@ -19,3 +21,18 @@ impl<'a> LayoutContext<'a> {
         &self.style_context
     }
 }
+
+pub(crate) type LayoutFontContext = FontContext<FontCacheThread>;
+
+thread_local!(static FONT_CONTEXT: RefCell<Option<LayoutFontContext>> = RefCell::new(None));
+
+pub(crate) fn with_thread_local_font_context<F, R>(layout_context: &LayoutContext, f: F) -> R
+where
+    F: FnOnce(&mut LayoutFontContext) -> R,
+{
+    FONT_CONTEXT.with(|font_context| {
+        f(font_context.borrow_mut().get_or_insert_with(|| {
+            FontContext::new(layout_context.font_cache_thread.lock().unwrap().clone())
+        }))
+    })
+}
diff --git a/components/layout_2020/display_list.rs b/components/layout_2020/display_list.rs
index c153b04294c..5dc5ecb96ad 100644
--- a/components/layout_2020/display_list.rs
+++ b/components/layout_2020/display_list.rs
@@ -6,7 +6,10 @@ use crate::fragments::{BoxFragment, Fragment};
 use crate::geom::physical::{Rect, Vec2};
 use crate::style_ext::ComputedValuesExt;
 use app_units::Au;
-use euclid::{self, SideOffsets2D};
+use euclid::{Point2D, SideOffsets2D};
+use gfx::text::glyph::GlyphStore;
+use servo_geometry::MaxRect;
+use std::sync::Arc;
 use style::values::computed::{BorderStyle, Length};
 use webrender_api::{self as wr, units, CommonItemProperties, PrimitiveFlags};
 
@@ -50,9 +53,30 @@ impl Fragment {
                     child.build_display_list(builder, is_contentful, &rect)
                 }
             },
-            Fragment::Text(_) => {
+            Fragment::Text(t) => {
                 is_contentful.0 = true;
-                // FIXME
+                let rect = t
+                    .content_rect
+                    .to_physical(t.parent_style.writing_mode(), containing_block)
+                    .translate(&containing_block.top_left);
+                let mut baseline_origin = rect.top_left.clone();
+                baseline_origin.y += t.ascent;
+                let common = CommonItemProperties {
+                    clip_rect: rect.clone().into(),
+                    clip_id: wr::ClipId::root(builder.pipeline_id),
+                    spatial_id: wr::SpatialId::root_scroll_node(builder.pipeline_id),
+                    hit_info: None,
+                    // TODO(gw): Make use of the WR backface visibility functionality.
+                    flags: PrimitiveFlags::default(),
+                };
+                let glyphs = glyphs(&t.glyphs, baseline_origin);
+                if glyphs.is_empty() {
+                    return;
+                }
+                let color = t.parent_style.clone_color();
+                builder
+                    .wr
+                    .push_text(&common, rect.into(), &glyphs, t.font_key, rgba(color), None);
             },
         }
     }
@@ -154,3 +178,28 @@ fn rgba(rgba: cssparser::RGBA) -> wr::ColorF {
         rgba.alpha_f32(),
     )
 }
+
+fn glyphs(glyph_runs: &[Arc<GlyphStore>], mut origin: Vec2<Length>) -> Vec<wr::GlyphInstance> {
+    use gfx_traits::ByteIndex;
+    use range::Range;
+
+    let mut glyphs = vec![];
+    for run in glyph_runs {
+        for glyph in run.iter_glyphs_for_byte_range(&Range::new(ByteIndex(0), run.len())) {
+            if !run.is_whitespace() {
+                let glyph_offset = glyph.offset().unwrap_or(Point2D::zero());
+                let point = units::LayoutPoint::new(
+                    origin.x.px() + glyph_offset.x.to_f32_px(),
+                    origin.y.px() + glyph_offset.y.to_f32_px(),
+                );
+                let glyph = wr::GlyphInstance {
+                    index: glyph.id(),
+                    point,
+                };
+                glyphs.push(glyph);
+            }
+            origin.x += Length::from(glyph.advance());
+        }
+    }
+    glyphs
+}
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index 133654f32b7..e410fa269ec 100644
--- a/components/layout_2020/flow/inline.rs
+++ b/components/layout_2020/flow/inline.rs
@@ -2,9 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::context::LayoutContext;
 use crate::flow::float::FloatBox;
 use crate::flow::FlowChildren;
-use crate::fragments::{AnonymousFragment, BoxFragment, CollapsedBlockMargins, Fragment};
+use crate::fragments::{
+    AnonymousFragment, BoxFragment, CollapsedBlockMargins, Fragment, TextFragment,
+};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::positioned::{AbsolutelyPositionedBox, AbsolutelyPositionedFragment};
 use crate::replaced::ReplacedContent;
@@ -81,6 +84,7 @@ struct LinesBoxes {
 impl InlineFormattingContext {
     pub(super) fn layout<'a>(
         &'a self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
@@ -107,7 +111,7 @@ impl InlineFormattingContext {
                         let partial = inline.start_layout(&mut ifc);
                         ifc.partial_inline_boxes_stack.push(partial)
                     },
-                    InlineLevelBox::TextRun(run) => run.layout(&mut ifc),
+                    InlineLevelBox::TextRun(run) => run.layout(layout_context, &mut ifc),
                     InlineLevelBox::Atomic { style: _, contents } => {
                         // FIXME
                         match *contents {}
@@ -284,7 +288,141 @@ impl<'box_tree> PartialInlineBoxFragment<'box_tree> {
 }
 
 impl TextRun {
-    fn layout(&self, _ifc: &mut InlineFormattingContextState) {
-        // TODO
+    fn layout(&self, layout_context: &LayoutContext, ifc: &mut InlineFormattingContextState) {
+        use gfx::font::{ShapingFlags, ShapingOptions};
+        use style::computed_values::text_rendering::T as TextRendering;
+        use style::computed_values::word_break::T as WordBreak;
+        use style::values::generics::text::LineHeight;
+
+        let font_style = self.parent_style.clone_font();
+        let inherited_text_style = self.parent_style.get_inherited_text();
+        let letter_spacing = if inherited_text_style.letter_spacing.0.px() != 0. {
+            Some(app_units::Au::from(inherited_text_style.letter_spacing.0))
+        } else {
+            None
+        };
+
+        let mut flags = ShapingFlags::empty();
+        if letter_spacing.is_some() {
+            flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
+        }
+        if inherited_text_style.text_rendering == TextRendering::Optimizespeed {
+            flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
+            flags.insert(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
+        }
+        if inherited_text_style.word_break == WordBreak::KeepAll {
+            flags.insert(ShapingFlags::KEEP_ALL_FLAG);
+        }
+
+        let shaping_options = gfx::font::ShapingOptions {
+            letter_spacing,
+            word_spacing: inherited_text_style.word_spacing.to_hash_key(),
+            script: unicode_script::Script::Common,
+            flags,
+        };
+
+        let (font_ascent, font_line_gap, font_key, runs) =
+            crate::context::with_thread_local_font_context(layout_context, |font_context| {
+                let font_group = font_context.font_group(font_style);
+                let font = font_group
+                    .borrow_mut()
+                    .first(font_context)
+                    .expect("could not find font");
+                let mut font = font.borrow_mut();
+
+                let (runs, _break_at_start) = gfx::text::text_run::TextRun::break_and_shape(
+                    &mut font,
+                    &self.text,
+                    &shaping_options,
+                    &mut None,
+                );
+
+                (
+                    font.metrics.ascent,
+                    font.metrics.line_gap,
+                    font.font_key,
+                    runs,
+                )
+            });
+
+        let font_size = self.parent_style.get_font().font_size.size.0;
+        let mut runs = runs.iter();
+        loop {
+            let mut glyphs = vec![];
+            let mut advance_width = Length::zero();
+            let mut last_break_opportunity = None;
+            loop {
+                let next = runs.next();
+                if next
+                    .as_ref()
+                    .map_or(true, |run| run.glyph_store.is_whitespace())
+                {
+                    if advance_width > ifc.containing_block.inline_size - ifc.inline_position {
+                        if let Some((len, width, iter)) = last_break_opportunity.take() {
+                            glyphs.truncate(len);
+                            advance_width = width;
+                            runs = iter;
+                        }
+                        break;
+                    }
+                }
+                if let Some(run) = next {
+                    if run.glyph_store.is_whitespace() {
+                        last_break_opportunity = Some((glyphs.len(), advance_width, runs.clone()));
+                    }
+                    glyphs.push(run.glyph_store.clone());
+                    advance_width += Length::from(run.glyph_store.total_advance());
+                } else {
+                    break;
+                }
+            }
+            let line_height = match self.parent_style.get_inherited_text().line_height {
+                LineHeight::Normal => font_line_gap.into(),
+                LineHeight::Number(n) => font_size * n.0,
+                LineHeight::Length(l) => l.0,
+            };
+            let content_rect = Rect {
+                start_corner: Vec2 {
+                    block: Length::zero(),
+                    inline: ifc.inline_position - ifc.current_nesting_level.inline_start,
+                },
+                size: Vec2 {
+                    block: line_height,
+                    inline: advance_width,
+                },
+            };
+            ifc.inline_position += advance_width;
+            ifc.current_nesting_level
+                .max_block_size_of_fragments_so_far
+                .max_assign(line_height);
+            ifc.current_nesting_level
+                .fragments_so_far
+                .push(Fragment::Text(TextFragment {
+                    parent_style: self.parent_style.clone(),
+                    content_rect,
+                    ascent: font_ascent.into(),
+                    font_key,
+                    glyphs,
+                }));
+            if runs.is_empty() {
+                break;
+            } else {
+                // New line
+                ifc.current_nesting_level.inline_start = Length::zero();
+                let mut nesting_level = &mut ifc.current_nesting_level;
+                for partial in ifc.partial_inline_boxes_stack.iter_mut().rev() {
+                    partial.finish_layout(nesting_level, &mut ifc.inline_position, true);
+                    partial.start_corner.inline = Length::zero();
+                    partial.padding.inline_start = Length::zero();
+                    partial.border.inline_start = Length::zero();
+                    partial.margin.inline_start = Length::zero();
+                    partial.parent_nesting_level.inline_start = Length::zero();
+                    nesting_level = &mut partial.parent_nesting_level;
+                }
+                ifc.line_boxes
+                    .finish_line(nesting_level, ifc.containing_block);
+                ifc.inline_position = Length::zero();
+            }
+        }
     }
 }
diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index 2395380c5eb..b690e447cd7 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -4,6 +4,7 @@
 
 //! Flow layout, also known as block-and-inline layout.
 
+use crate::context::LayoutContext;
 use crate::flow::float::{FloatBox, FloatContext};
 use crate::flow::inline::InlineFormattingContext;
 use crate::fragments::{
@@ -67,6 +68,7 @@ struct CollapsibleWithParentStartMargin(bool);
 impl BlockFormattingContext {
     pub(super) fn layout<'a>(
         &'a self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
@@ -79,6 +81,7 @@ impl BlockFormattingContext {
             None
         };
         let mut flow_children = self.contents.layout(
+            layout_context,
             containing_block,
             tree_rank,
             absolutely_positioned_fragments,
@@ -97,6 +100,7 @@ impl BlockFormattingContext {
 impl BlockContainer {
     fn layout<'a>(
         &'a self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
@@ -105,6 +109,7 @@ impl BlockContainer {
     ) -> FlowChildren {
         match self {
             BlockContainer::BlockLevelBoxes(child_boxes) => layout_block_level_children(
+                layout_context,
                 child_boxes,
                 containing_block,
                 tree_rank,
@@ -112,14 +117,18 @@ impl BlockContainer {
                 float_context,
                 collapsible_with_parent_start_margin,
             ),
-            BlockContainer::InlineFormattingContext(ifc) => {
-                ifc.layout(containing_block, tree_rank, absolutely_positioned_fragments)
-            },
+            BlockContainer::InlineFormattingContext(ifc) => ifc.layout(
+                layout_context,
+                containing_block,
+                tree_rank,
+                absolutely_positioned_fragments,
+            ),
         }
     }
 }
 
 fn layout_block_level_children<'a>(
+    layout_context: &LayoutContext,
     child_boxes: &'a [Arc<BlockLevelBox>],
     containing_block: &ContainingBlock,
     tree_rank: usize,
@@ -201,6 +210,7 @@ fn layout_block_level_children<'a>(
             .enumerate()
             .map(|(tree_rank, box_)| {
                 let mut fragment = box_.layout(
+                    layout_context,
                     containing_block,
                     tree_rank,
                     absolutely_positioned_fragments,
@@ -218,6 +228,7 @@ fn layout_block_level_children<'a>(
                 absolutely_positioned_fragments,
                 |abspos_fragments, (tree_rank, box_)| {
                     box_.layout(
+                        layout_context,
                         containing_block,
                         tree_rank,
                         abspos_fragments,
@@ -255,6 +266,7 @@ fn layout_block_level_children<'a>(
 impl BlockLevelBox {
     fn layout<'a>(
         &'a self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
@@ -263,12 +275,14 @@ impl BlockLevelBox {
         match self {
             BlockLevelBox::SameFormattingContextBlock { style, contents } => {
                 Fragment::Box(layout_in_flow_non_replaced_block_level(
+                    layout_context,
                     containing_block,
                     absolutely_positioned_fragments,
                     style,
                     BlockLevelKind::SameFormattingContextBlock,
                     |containing_block, nested_abspos, collapsible_with_parent_start_margin| {
                         contents.layout(
+                            layout_context,
                             containing_block,
                             tree_rank,
                             nested_abspos,
@@ -284,12 +298,13 @@ impl BlockLevelBox {
                     match *replaced {}
                 },
                 Err(contents) => Fragment::Box(layout_in_flow_non_replaced_block_level(
+                    layout_context,
                     containing_block,
                     absolutely_positioned_fragments,
                     style,
                     BlockLevelKind::EstablishesAnIndependentFormattingContext,
                     |containing_block, nested_abspos, _| {
-                        contents.layout(containing_block, tree_rank, nested_abspos)
+                        contents.layout(layout_context, containing_block, tree_rank, nested_abspos)
                     },
                 )),
             },
@@ -314,6 +329,7 @@ enum BlockLevelKind {
 /// https://drafts.csswg.org/css2/visudet.html#blockwidth
 /// https://drafts.csswg.org/css2/visudet.html#normal-block
 fn layout_in_flow_non_replaced_block_level<'a>(
+    layout_context: &LayoutContext,
     containing_block: &ContainingBlock,
     absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
     style: &Arc<ComputedValues>,
@@ -433,6 +449,7 @@ fn layout_in_flow_non_replaced_block_level<'a>(
     };
     if style.get_box().position == Position::Relative {
         AbsolutelyPositionedFragment::in_positioned_containing_block(
+            layout_context,
             &nested_abspos,
             &mut flow_children.fragments,
             &content_rect.size,
diff --git a/components/layout_2020/flow/root.rs b/components/layout_2020/flow/root.rs
index 54cc1eef07f..a1831c6433a 100644
--- a/components/layout_2020/flow/root.rs
+++ b/components/layout_2020/flow/root.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::context::LayoutContext;
 use crate::display_list::IsContentful;
 use crate::dom_traversal::{Contents, NodeExt};
 use crate::flow::construct::ContainsFloats;
@@ -98,7 +99,11 @@ fn construct_for_root_element<'dom>(
 }
 
 impl BoxTreeRoot {
-    pub fn layout(&self, viewport: geom::Size<CSSPixel>) -> FragmentTreeRoot {
+    pub fn layout(
+        &self,
+        layout_context: &LayoutContext,
+        viewport: geom::Size<CSSPixel>,
+    ) -> FragmentTreeRoot {
         let initial_containing_block_size = Vec2 {
             inline: Length::new(viewport.width),
             block: Length::new(viewport.height),
@@ -114,6 +119,7 @@ impl BoxTreeRoot {
         let dummy_tree_rank = 0;
         let mut absolutely_positioned_fragments = vec![];
         let mut flow_children = self.0.layout(
+            layout_context,
             &initial_containing_block,
             dummy_tree_rank,
             &mut absolutely_positioned_fragments,
@@ -126,7 +132,7 @@ impl BoxTreeRoot {
         flow_children.fragments.par_extend(
             absolutely_positioned_fragments
                 .par_iter()
-                .map(|a| a.layout(&initial_containing_block)),
+                .map(|a| a.layout(layout_context, &initial_containing_block)),
         );
         FragmentTreeRoot(flow_children.fragments)
     }
diff --git a/components/layout_2020/fragments.rs b/components/layout_2020/fragments.rs
index ceb2fdf7971..a0ea097abb6 100644
--- a/components/layout_2020/fragments.rs
+++ b/components/layout_2020/fragments.rs
@@ -4,11 +4,13 @@
 
 use crate::geom::flow_relative::{Rect, Sides};
 use crate::style_ext::{Direction, WritingMode};
-// use crate::text::ShapedSegment;
-use servo_arc::Arc;
+use gfx::text::glyph::GlyphStore;
+use servo_arc::Arc as ServoArc;
+use std::sync::Arc;
 use style::properties::ComputedValues;
 use style::values::computed::Length;
 use style::Zero;
+use webrender_api::FontInstanceKey;
 
 pub(crate) enum Fragment {
     Box(BoxFragment),
@@ -17,7 +19,7 @@ pub(crate) enum Fragment {
 }
 
 pub(crate) struct BoxFragment {
-    pub style: Arc<ComputedValues>,
+    pub style: ServoArc<ComputedValues>,
     pub children: Vec<Fragment>,
 
     /// From the containing block’s start corner…?
@@ -52,9 +54,11 @@ pub(crate) struct AnonymousFragment {
 }
 
 pub(crate) struct TextFragment {
-    pub parent_style: Arc<ComputedValues>,
+    pub parent_style: ServoArc<ComputedValues>,
     pub content_rect: Rect<Length>,
-    // pub text: ShapedSegment,
+    pub ascent: Length,
+    pub font_key: FontInstanceKey,
+    pub glyphs: Vec<Arc<GlyphStore>>,
 }
 
 impl AnonymousFragment {
diff --git a/components/layout_2020/lib.rs b/components/layout_2020/lib.rs
index 052cb4b0540..c0892553f35 100644
--- a/components/layout_2020/lib.rs
+++ b/components/layout_2020/lib.rs
@@ -7,6 +7,7 @@
 #![allow(unused_imports)]
 #![allow(unused_variables)]
 #![deny(unsafe_code)]
+#![feature(exact_size_is_empty)]
 
 #[macro_use]
 extern crate serde;
@@ -33,6 +34,7 @@ pub mod wrapper;
 
 pub use flow::{BoxTreeRoot, FragmentTreeRoot};
 
+use crate::context::LayoutContext;
 use crate::dom_traversal::{Contents, NodeExt};
 use crate::flow::{BlockFormattingContext, FlowChildren};
 use crate::geom::flow_relative::Vec2;
@@ -87,13 +89,19 @@ impl IndependentFormattingContext {
 
     fn layout<'a>(
         &'a self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
     ) -> FlowChildren {
         match self.as_replaced() {
             Ok(replaced) => match *replaced {},
-            Err(ifc) => ifc.layout(containing_block, tree_rank, absolutely_positioned_fragments),
+            Err(ifc) => ifc.layout(
+                layout_context,
+                containing_block,
+                tree_rank,
+                absolutely_positioned_fragments,
+            ),
         }
     }
 }
@@ -101,14 +109,18 @@ impl IndependentFormattingContext {
 impl<'a> NonReplacedIFC<'a> {
     fn layout(
         &self,
+        layout_context: &LayoutContext,
         containing_block: &ContainingBlock,
         tree_rank: usize,
         absolutely_positioned_fragments: &mut Vec<AbsolutelyPositionedFragment<'a>>,
     ) -> FlowChildren {
         match self {
-            NonReplacedIFC::Flow(bfc) => {
-                bfc.layout(containing_block, tree_rank, absolutely_positioned_fragments)
-            },
+            NonReplacedIFC::Flow(bfc) => bfc.layout(
+                layout_context,
+                containing_block,
+                tree_rank,
+                absolutely_positioned_fragments,
+            ),
         }
     }
 }
diff --git a/components/layout_2020/positioned.rs b/components/layout_2020/positioned.rs
index 55888fb8842..b37a5ed4a70 100644
--- a/components/layout_2020/positioned.rs
+++ b/components/layout_2020/positioned.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::context::LayoutContext;
 use crate::fragments::{AnonymousFragment, BoxFragment, CollapsedBlockMargins, Fragment};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::style_ext::{ComputedValuesExt, Direction, WritingMode};
@@ -94,6 +95,7 @@ impl AbsolutelyPositionedBox {
 
 impl<'a> AbsolutelyPositionedFragment<'a> {
     pub(crate) fn in_positioned_containing_block(
+        layout_context: &LayoutContext,
         absolute: &[Self],
         fragments: &mut Vec<Fragment>,
         content_rect_size: &Vec2<Length>,
@@ -116,14 +118,18 @@ impl<'a> AbsolutelyPositionedFragment<'a> {
         fragments.push(Fragment::Anonymous(AnonymousFragment {
             children: absolute
                 .par_iter()
-                .map(|a| a.layout(&containing_block))
+                .map(|a| a.layout(layout_context, &containing_block))
                 .collect(),
             rect: padding_rect,
             mode,
         }))
     }
 
-    pub(crate) fn layout(&self, containing_block: &DefiniteContainingBlock) -> Fragment {
+    pub(crate) fn layout(
+        &self,
+        layout_context: &LayoutContext,
+        containing_block: &DefiniteContainingBlock,
+    ) -> Fragment {
         let style = &self.absolutely_positioned_box.style;
         let cbis = containing_block.size.inline;
         let cbbs = containing_block.size.block;
@@ -269,6 +275,7 @@ impl<'a> AbsolutelyPositionedFragment<'a> {
         let dummy_tree_rank = 0;
         let mut absolutely_positioned_fragments = vec![];
         let mut flow_children = self.absolutely_positioned_box.contents.layout(
+            layout_context,
             &containing_block_for_children,
             dummy_tree_rank,
             &mut absolutely_positioned_fragments,
@@ -297,6 +304,7 @@ impl<'a> AbsolutelyPositionedFragment<'a> {
         };
 
         AbsolutelyPositionedFragment::in_positioned_containing_block(
+            layout_context,
             &absolutely_positioned_fragments,
             &mut flow_children.fragments,
             &content_rect.size,
diff --git a/components/layout_thread_2020/lib.rs b/components/layout_thread_2020/lib.rs
index bf18c584231..e8fdb1cfccd 100644
--- a/components/layout_thread_2020/lib.rs
+++ b/components/layout_thread_2020/lib.rs
@@ -88,7 +88,7 @@ use style::context::{SharedStyleContext, ThreadLocalStyleContextCreationInfo};
 use style::dom::{TDocument, TElement, TNode};
 use style::driver;
 use style::error_reporting::RustLogReporter;
-use style::global_style_data::GLOBAL_STYLE_DATA;
+use style::global_style_data::{GLOBAL_STYLE_DATA, STYLE_THREAD_POOL};
 use style::invalidation::element::restyle_hints::RestyleHint;
 use style::media_queries::{Device, MediaList, MediaType};
 use style::properties::PropertyId;
@@ -1087,16 +1087,29 @@ impl LayoutThread {
             RecalcStyle::pre_traverse(element, shared)
         };
 
-        if token.should_traverse() {
+        let rayon_pool = STYLE_THREAD_POOL.pool();
+        let rayon_pool = rayon_pool.as_ref().unwrap();
+
+        let box_tree = if token.should_traverse() {
             driver::traverse_dom(&traversal, token, None);
 
             let shared = DomTraversal::<ServoLayoutElement>::shared_context(&traversal);
-            let box_tree =
-                BoxTreeRoot::construct(shared, document.root_element().unwrap().as_node());
-            let fragment_tree = box_tree.layout(Size2D::new(
+            let root_node = document.root_element().unwrap().as_node();
+            let box_tree = rayon_pool.install(|| BoxTreeRoot::construct(shared, root_node));
+            Some(box_tree)
+        } else {
+            None
+        };
+
+        layout_context = traversal.destroy();
+
+        if let Some(box_tree) = box_tree {
+            let viewport_size = Size2D::new(
                 self.viewport_size.width.to_f32_px(),
                 self.viewport_size.height.to_f32_px(),
-            ));
+            );
+            let fragment_tree =
+                rayon_pool.install(|| box_tree.layout(&layout_context, viewport_size));
             *self.box_tree_root.borrow_mut() = Some(box_tree);
             *self.fragment_tree_root.borrow_mut() = Some(fragment_tree);
         }
@@ -1105,8 +1118,6 @@ impl LayoutThread {
             unsafe { element.unset_snapshot_flags() }
         }
 
-        layout_context = traversal.destroy();
-
         // GC the rule tree if some heuristics are met.
         unsafe {
             layout_context.style_context.stylist.rule_tree().maybe_gc();
diff --git a/components/script/Cargo.toml b/components/script/Cargo.toml
index c44a9a06a54..855d3d4dbc8 100644
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@@ -113,6 +113,7 @@ utf-8 = "0.7"
 uuid = {version = "0.8", features = ["v4"]}
 xml5ever = "0.16"
 webdriver = "0.40"
+webgpu = {path = "../webgpu"}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
 webvr_traits = {path = "../webvr_traits"}
 webxr-api = {git = "https://github.com/servo/webxr", features = ["ipc"]}
diff --git a/components/script/dom/bindings/codegen/Bindings.conf b/components/script/dom/bindings/codegen/Bindings.conf
index 3ff7a044b53..5dc9e141ed5 100644
--- a/components/script/dom/bindings/codegen/Bindings.conf
+++ b/components/script/dom/bindings/codegen/Bindings.conf
@@ -134,7 +134,10 @@ DOMInterfaces = {
 
 'XR': {
     'inCompartments': ['SupportsSessionMode', 'RequestSession'],
-}
+},
 
+'GPU': {
+    'inCompartments': ['RequestAdapter'],
+}
 
 }
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index 2051a1a19d8..fbd4da02d5b 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -145,6 +145,7 @@ use tendril::stream::LossyDecoder;
 use tendril::{StrTendril, TendrilSink};
 use time::{Duration, Timespec};
 use uuid::Uuid;
+use webgpu::{WebGPU, WebGPUAdapter};
 use webrender_api::{DocumentId, ImageKey, RenderApiSender};
 use webvr_traits::{WebVRGamepadData, WebVRGamepadHand, WebVRGamepadState};
 use webxr_api::SwapChainId as WebXRSwapChainId;
@@ -502,6 +503,8 @@ unsafe_no_jsmanaged_fields!(WebGLTextureId);
 unsafe_no_jsmanaged_fields!(WebGLVertexArrayId);
 unsafe_no_jsmanaged_fields!(WebGLVersion);
 unsafe_no_jsmanaged_fields!(WebGLSLVersion);
+unsafe_no_jsmanaged_fields!(WebGPU);
+unsafe_no_jsmanaged_fields!(WebGPUAdapter);
 unsafe_no_jsmanaged_fields!(WebXRSwapChainId);
 unsafe_no_jsmanaged_fields!(MediaList);
 unsafe_no_jsmanaged_fields!(WebVRGamepadData, WebVRGamepadState, WebVRGamepadHand);
diff --git a/components/script/dom/formdataevent.rs b/components/script/dom/formdataevent.rs
index f7ebb57bbfb..c380abf217a 100644
--- a/components/script/dom/formdataevent.rs
+++ b/components/script/dom/formdataevent.rs
@@ -5,7 +5,7 @@
 use crate::dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use crate::dom::bindings::codegen::Bindings::FormDataEventBinding;
 use crate::dom::bindings::codegen::Bindings::FormDataEventBinding::FormDataEventMethods;
-use crate::dom::bindings::error::{Error, Fallible};
+use crate::dom::bindings::error::Fallible;
 use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::reflector::{reflect_dom_object, DomObject};
 use crate::dom::bindings::root::{Dom, DomRoot};
@@ -56,21 +56,12 @@ impl FormDataEvent {
         let bubbles = EventBubbles::from(init.parent.bubbles);
         let cancelable = EventCancelable::from(init.parent.cancelable);
 
-        let form_data = match init.formData {
-            Some(ref form_data) => form_data.clone(),
-            None => {
-                return Err(Error::Type(
-                    "required member formData is undefined".to_string(),
-                ));
-            },
-        };
-
         let event = FormDataEvent::new(
             &window.global(),
             Atom::from(type_),
             bubbles,
             cancelable,
-            &*form_data,
+            &*init.formData.clone(),
         );
 
         Ok(event)
diff --git a/components/script/dom/gpu.rs b/components/script/dom/gpu.rs
new file mode 100644
index 00000000000..cbde108bc01
--- /dev/null
+++ b/components/script/dom/gpu.rs
@@ -0,0 +1,158 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::compartments::InCompartment;
+use crate::dom::bindings::codegen::Bindings::GPUBinding::GPURequestAdapterOptions;
+use crate::dom::bindings::codegen::Bindings::GPUBinding::{self, GPUMethods, GPUPowerPreference};
+use crate::dom::bindings::error::Error;
+use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
+use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::bindings::str::DOMString;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::gpuadapter::GPUAdapter;
+use crate::dom::promise::Promise;
+use crate::task_source::TaskSource;
+use dom_struct::dom_struct;
+use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::router::ROUTER;
+use js::jsapi::Heap;
+use std::rc::Rc;
+use webgpu::wgpu;
+use webgpu::{WebGPU, WebGPURequest, WebGPUResponse, WebGPUResponseResult};
+
+#[dom_struct]
+pub struct GPU {
+    reflector_: Reflector,
+}
+
+impl GPU {
+    pub fn new_inherited() -> GPU {
+        GPU {
+            reflector_: Reflector::new(),
+        }
+    }
+
+    pub fn new(global: &GlobalScope) -> DomRoot<GPU> {
+        reflect_dom_object(Box::new(GPU::new_inherited()), global, GPUBinding::Wrap)
+    }
+
+    fn wgpu_channel(&self) -> Option<WebGPU> {
+        self.global().as_window().webgpu_channel()
+    }
+}
+
+pub trait AsyncWGPUListener {
+    fn handle_response(&self, response: WebGPUResponse, promise: &Rc<Promise>);
+}
+
+struct WGPUResponse<T: AsyncWGPUListener + DomObject> {
+    trusted: TrustedPromise,
+    receiver: Trusted<T>,
+}
+
+impl<T: AsyncWGPUListener + DomObject> WGPUResponse<T> {
+    #[allow(unrooted_must_root)]
+    fn response(self, response: WebGPUResponseResult) {
+        let promise = self.trusted.root();
+        match response {
+            Ok(response) => self.receiver.root().handle_response(response, &promise),
+            Err(error) => promise.reject_error(Error::Type(format!(
+                "Received error from WebGPU thread: {}",
+                error
+            ))),
+        }
+    }
+}
+
+pub fn response_async<T: AsyncWGPUListener + DomObject + 'static>(
+    promise: &Rc<Promise>,
+    receiver: &T,
+) -> IpcSender<WebGPUResponseResult> {
+    let (action_sender, action_receiver) = ipc::channel().unwrap();
+    let (task_source, canceller) = receiver
+        .global()
+        .as_window()
+        .task_manager()
+        .dom_manipulation_task_source_with_canceller();
+    let mut trusted = Some(TrustedPromise::new(promise.clone()));
+    let trusted_receiver = Trusted::new(receiver);
+    ROUTER.add_route(
+        action_receiver.to_opaque(),
+        Box::new(move |message| {
+            let trusted = if let Some(trusted) = trusted.take() {
+                trusted
+            } else {
+                error!("WebGPU callback called twice!");
+                return;
+            };
+
+            let context = WGPUResponse {
+                trusted,
+                receiver: trusted_receiver.clone(),
+            };
+            let result = task_source.queue_with_canceller(
+                task!(process_webgpu_task: move|| {
+                    context.response(message.to().unwrap());
+                }),
+                &canceller,
+            );
+            if let Err(err) = result {
+                error!("Failed to queue GPU listener-task: {:?}", err);
+            }
+        }),
+    );
+    action_sender
+}
+
+impl GPUMethods for GPU {
+    // https://gpuweb.github.io/gpuweb/#dom-gpu-requestadapter
+    fn RequestAdapter(
+        &self,
+        options: &GPURequestAdapterOptions,
+        comp: InCompartment,
+    ) -> Rc<Promise> {
+        let promise = Promise::new_in_current_compartment(&self.global(), comp);
+        let sender = response_async(&promise, self);
+        let power_preference = match options.powerPreference {
+            Some(GPUPowerPreference::Low_power) => wgpu::PowerPreference::LowPower,
+            Some(GPUPowerPreference::High_performance) => wgpu::PowerPreference::HighPerformance,
+            None => wgpu::PowerPreference::Default,
+        };
+
+        match self.wgpu_channel() {
+            Some(channel) => {
+                channel
+                    .0
+                    .send(WebGPURequest::RequestAdapter(
+                        sender,
+                        wgpu::RequestAdapterOptions { power_preference },
+                    ))
+                    .unwrap();
+            },
+            None => promise.reject_error(Error::Type("No WebGPU thread...".to_owned())),
+        };
+        promise
+    }
+}
+
+impl AsyncWGPUListener for GPU {
+    fn handle_response(&self, response: WebGPUResponse, promise: &Rc<Promise>) {
+        match response {
+            WebGPUResponse::RequestAdapter(name, adapter) => {
+                let adapter = GPUAdapter::new(
+                    &self.global(),
+                    DOMString::from(name),
+                    Heap::default(),
+                    adapter,
+                );
+                promise.resolve_native(&adapter);
+            },
+            response => promise.reject_error(Error::Type(format!(
+                "Wrong response received for GPU from WebGPU thread {:?}",
+                response,
+            ))),
+        }
+    }
+}
diff --git a/components/script/dom/gpuadapter.rs b/components/script/dom/gpuadapter.rs
new file mode 100644
index 00000000000..ec970439e8a
--- /dev/null
+++ b/components/script/dom/gpuadapter.rs
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::dom::bindings::codegen::Bindings::GPUAdapterBinding::{self, GPUAdapterMethods};
+use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::bindings::str::DOMString;
+use crate::dom::globalscope::GlobalScope;
+use crate::script_runtime::JSContext as SafeJSContext;
+use dom_struct::dom_struct;
+use js::jsapi::{Heap, JSObject};
+use std::ptr::NonNull;
+use webgpu::WebGPUAdapter;
+
+#[dom_struct]
+pub struct GPUAdapter {
+    reflector_: Reflector,
+    name: DOMString,
+    #[ignore_malloc_size_of = "mozjs"]
+    extensions: Heap<*mut JSObject>,
+    adapter: WebGPUAdapter,
+}
+
+impl GPUAdapter {
+    pub fn new_inherited(
+        name: DOMString,
+        extensions: Heap<*mut JSObject>,
+        adapter: WebGPUAdapter,
+    ) -> GPUAdapter {
+        GPUAdapter {
+            reflector_: Reflector::new(),
+            name,
+            extensions,
+            adapter,
+        }
+    }
+
+    pub fn new(
+        global: &GlobalScope,
+        name: DOMString,
+        extensions: Heap<*mut JSObject>,
+        adapter: WebGPUAdapter,
+    ) -> DomRoot<GPUAdapter> {
+        reflect_dom_object(
+            Box::new(GPUAdapter::new_inherited(name, extensions, adapter)),
+            global,
+            GPUAdapterBinding::Wrap,
+        )
+    }
+}
+
+impl GPUAdapterMethods for GPUAdapter {
+    // https://gpuweb.github.io/gpuweb/#dom-gpuadapter-name
+    fn Name(&self) -> DOMString {
+        self.name.clone()
+    }
+
+    // https://gpuweb.github.io/gpuweb/#dom-gpuadapter-extensions
+    fn Extensions(&self, _cx: SafeJSContext) -> NonNull<JSObject> {
+        NonNull::new(self.extensions.get()).unwrap()
+    }
+}
diff --git a/components/script/dom/mod.rs b/components/script/dom/mod.rs
index ef562931bee..9fbf2e0cc6e 100644
--- a/components/script/dom/mod.rs
+++ b/components/script/dom/mod.rs
@@ -315,6 +315,8 @@ pub mod gamepadbuttonlist;
 pub mod gamepadevent;
 pub mod gamepadlist;
 pub mod globalscope;
+pub mod gpu;
+pub mod gpuadapter;
 pub mod hashchangeevent;
 pub mod headers;
 pub mod history;
diff --git a/components/script/dom/navigator.rs b/components/script/dom/navigator.rs
index 127883dd956..cb8fb2365cd 100644
--- a/components/script/dom/navigator.rs
+++ b/components/script/dom/navigator.rs
@@ -11,6 +11,7 @@ use crate::dom::bindings::root::{DomRoot, MutNullableDom};
 use crate::dom::bindings::str::DOMString;
 use crate::dom::bluetooth::Bluetooth;
 use crate::dom::gamepadlist::GamepadList;
+use crate::dom::gpu::GPU;
 use crate::dom::mediadevices::MediaDevices;
 use crate::dom::mediasession::MediaSession;
 use crate::dom::mimetypearray::MimeTypeArray;
@@ -36,6 +37,7 @@ pub struct Navigator {
     gamepads: MutNullableDom<GamepadList>,
     permissions: MutNullableDom<Permissions>,
     mediasession: MutNullableDom<MediaSession>,
+    gpu: MutNullableDom<GPU>,
 }
 
 impl Navigator {
@@ -51,6 +53,7 @@ impl Navigator {
             gamepads: Default::default(),
             permissions: Default::default(),
             mediasession: Default::default(),
+            gpu: Default::default(),
         }
     }
 
@@ -205,4 +208,9 @@ impl NavigatorMethods for Navigator {
             MediaSession::new(window)
         })
     }
+
+    // https://gpuweb.github.io/gpuweb/#dom-navigator-gpu
+    fn Gpu(&self) -> DomRoot<GPU> {
+        self.gpu.or_init(|| GPU::new(&self.global()))
+    }
 }
diff --git a/components/script/dom/webidls/FormDataEvent.webidl b/components/script/dom/webidls/FormDataEvent.webidl
index 5160a396081..0cb81b93962 100644
--- a/components/script/dom/webidls/FormDataEvent.webidl
+++ b/components/script/dom/webidls/FormDataEvent.webidl
@@ -5,10 +5,10 @@
 // https://html.spec.whatwg.org/multipage/#the-formdataevent-interface
 [Exposed=Window]
 interface FormDataEvent : Event {
-  [Throws] constructor(DOMString type, optional FormDataEventInit eventInitDict = {});
+  [Throws] constructor(DOMString type, FormDataEventInit eventInitDict);
   readonly attribute FormData formData;
 };
 
 dictionary FormDataEventInit : EventInit {
-  /*required*/ FormData formData;
+  required FormData formData;
 };
diff --git a/components/script/dom/webidls/GPU.webidl b/components/script/dom/webidls/GPU.webidl
new file mode 100644
index 00000000000..856c5027569
--- /dev/null
+++ b/components/script/dom/webidls/GPU.webidl
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://gpuweb.github.io/gpuweb/#gpu-interface
+[Exposed=(Window, DedicatedWorker), Pref="dom.webgpu.enabled"]
+interface GPU {
+    // May reject with DOMException  // TODO: DOMException("OperationError")?
+    Promise<GPUAdapter> requestAdapter(optional GPURequestAdapterOptions options = {});
+};
+
+// https://gpuweb.github.io/gpuweb/#dictdef-gpurequestadapteroptions
+dictionary GPURequestAdapterOptions {
+    GPUPowerPreference powerPreference;
+};
+
+// https://gpuweb.github.io/gpuweb/#enumdef-gpupowerpreference
+enum GPUPowerPreference {
+    "low-power",
+    "high-performance"
+};
diff --git a/components/script/dom/webidls/GPUAdapter.webidl b/components/script/dom/webidls/GPUAdapter.webidl
new file mode 100644
index 00000000000..0c2118a5f56
--- /dev/null
+++ b/components/script/dom/webidls/GPUAdapter.webidl
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://gpuweb.github.io/gpuweb/#gpuadapter
+[Exposed=(Window, DedicatedWorker), Pref="dom.webgpu.enabled"]
+interface GPUAdapter {
+    readonly attribute DOMString name;
+    readonly attribute object extensions;
+    //readonly attribute GPULimits limits; Don’t expose higher limits for now.
+
+    // May reject with DOMException  // TODO: DOMException("OperationError")?
+    // Promise<GPUDevice> requestDevice(optional GPUDeviceDescriptor descriptor = {});
+};
diff --git a/components/script/dom/webidls/Navigator.webidl b/components/script/dom/webidls/Navigator.webidl
index 6b5b1e1f283..b51e2ba52f0 100644
--- a/components/script/dom/webidls/Navigator.webidl
+++ b/components/script/dom/webidls/Navigator.webidl
@@ -75,3 +75,8 @@ partial interface Navigator {
 partial interface Navigator {
     [Pref="dom.gamepad.enabled"] GamepadList getGamepads();
 };
+
+[Exposed=Window]
+partial interface Navigator {
+    [SameObject, Pref="dom.webgpu.enabled"] readonly attribute GPU gpu;
+};
diff --git a/components/script/dom/webidls/WorkerNavigator.webidl b/components/script/dom/webidls/WorkerNavigator.webidl
index 119e22ea11f..5be43960802 100644
--- a/components/script/dom/webidls/WorkerNavigator.webidl
+++ b/components/script/dom/webidls/WorkerNavigator.webidl
@@ -15,3 +15,8 @@ WorkerNavigator includes NavigatorLanguage;
 partial interface WorkerNavigator {
   [Pref="dom.permissions.enabled"] readonly attribute Permissions permissions;
 };
+
+[Exposed=DedicatedWorker]
+partial interface WorkerNavigator {
+    [SameObject, Pref="dom.webgpu.enabled"] readonly attribute GPU gpu;
+};
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 0c3a2db0899..4ae94520f1f 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -136,6 +136,7 @@ use style::str::HTML_SPACE_CHARACTERS;
 use style::stylesheets::CssRuleType;
 use style_traits::{CSSPixel, DevicePixel, ParsingMode};
 use url::Position;
+use webgpu::WebGPU;
 use webrender_api::units::{DeviceIntPoint, DeviceIntSize, LayoutPixel};
 use webrender_api::{DocumentId, ExternalScrollId, RenderApiSender};
 use webvr_traits::WebVRMsg;
@@ -267,6 +268,10 @@ pub struct Window {
     #[ignore_malloc_size_of = "channels are hard"]
     webgl_chan: Option<WebGLChan>,
 
+    #[ignore_malloc_size_of = "channels are hard"]
+    /// A handle for communicating messages to the WebGPU threads.
+    webgpu: Option<WebGPU>,
+
     /// A handle for communicating messages to the webvr thread, if available.
     #[ignore_malloc_size_of = "channels are hard"]
     webvr_chan: Option<IpcSender<WebVRMsg>>,
@@ -462,6 +467,10 @@ impl Window {
             .map(|chan| WebGLCommandSender::new(chan.clone(), self.get_event_loop_waker()))
     }
 
+    pub fn webgpu_channel(&self) -> Option<WebGPU> {
+        self.webgpu.clone()
+    }
+
     pub fn webvr_thread(&self) -> Option<IpcSender<WebVRMsg>> {
         self.webvr_chan.clone()
     }
@@ -2206,6 +2215,7 @@ impl Window {
         navigation_start: u64,
         navigation_start_precise: u64,
         webgl_chan: Option<WebGLChan>,
+        webgpu: Option<WebGPU>,
         webvr_chan: Option<IpcSender<WebVRMsg>>,
         webxr_registry: webxr_api::Registry,
         microtask_queue: Rc<MicrotaskQueue>,
@@ -2285,6 +2295,7 @@ impl Window {
             media_query_lists: DOMTracker::new(),
             test_runner: Default::default(),
             webgl_chan,
+            webgpu,
             webvr_chan,
             webxr_registry,
             permission_state_invocation_results: Default::default(),
diff --git a/components/script/dom/workernavigator.rs b/components/script/dom/workernavigator.rs
index 92dfa9951e5..cc1dfee13bd 100644
--- a/components/script/dom/workernavigator.rs
+++ b/components/script/dom/workernavigator.rs
@@ -7,6 +7,7 @@ use crate::dom::bindings::codegen::Bindings::WorkerNavigatorBinding::WorkerNavig
 use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
 use crate::dom::bindings::root::{DomRoot, MutNullableDom};
 use crate::dom::bindings::str::DOMString;
+use crate::dom::gpu::GPU;
 use crate::dom::navigatorinfo;
 use crate::dom::permissions::Permissions;
 use crate::dom::workerglobalscope::WorkerGlobalScope;
@@ -17,6 +18,7 @@ use dom_struct::dom_struct;
 pub struct WorkerNavigator {
     reflector_: Reflector,
     permissions: MutNullableDom<Permissions>,
+    gpu: MutNullableDom<GPU>,
 }
 
 impl WorkerNavigator {
@@ -24,6 +26,7 @@ impl WorkerNavigator {
         WorkerNavigator {
             reflector_: Reflector::new(),
             permissions: Default::default(),
+            gpu: Default::default(),
         }
     }
 
@@ -97,4 +100,9 @@ impl WorkerNavigatorMethods for WorkerNavigator {
         self.permissions
             .or_init(|| Permissions::new(&self.global()))
     }
+
+    // https://gpuweb.github.io/gpuweb/#dom-navigator-gpu
+    fn Gpu(&self) -> DomRoot<GPU> {
+        self.gpu.or_init(|| GPU::new(&self.global()))
+    }
 }
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index eb6e267c740..b69eb851f2f 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -163,6 +163,7 @@ use style::dom::OpaqueNode;
 use style::thread_state::{self, ThreadState};
 use time::{at_utc, get_time, precise_time_ns, Timespec};
 use url::Position;
+use webgpu::WebGPU;
 use webrender_api::units::LayoutPixel;
 use webrender_api::{DocumentId, RenderApiSender};
 use webvr_traits::{WebVREvent, WebVRMsg};
@@ -629,6 +630,9 @@ pub struct ScriptThread {
     /// A handle to the WebGL thread
     webgl_chan: Option<WebGLPipeline>,
 
+    /// A handle to the WebGPU threads
+    webgpu: Option<WebGPU>,
+
     /// A handle to the webvr thread, if available
     webvr_chan: Option<IpcSender<WebVRMsg>>,
 
@@ -1338,6 +1342,7 @@ impl ScriptThread {
             layout_to_constellation_chan: state.layout_to_constellation_chan,
 
             webgl_chan: state.webgl_chan,
+            webgpu: state.webgpu,
             webvr_chan: state.webvr_chan,
             webxr_registry: state.webxr_registry,
 
@@ -3247,6 +3252,7 @@ impl ScriptThread {
             incomplete.navigation_start,
             incomplete.navigation_start_precise,
             self.webgl_chan.as_ref().map(|chan| chan.channel()),
+            self.webgpu.clone(),
             self.webvr_chan.clone(),
             self.webxr_registry.clone(),
             self.microtask_queue.clone(),
diff --git a/components/script_traits/Cargo.toml b/components/script_traits/Cargo.toml
index 3fbdfd1f918..6d736ff3492 100644
--- a/components/script_traits/Cargo.toml
+++ b/components/script_traits/Cargo.toml
@@ -39,6 +39,7 @@ style_traits = {path = "../style_traits", features = ["servo"]}
 time = "0.1.12"
 url = "2.0"
 webdriver = "0.40"
+webgpu = {path = "../webgpu"}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
 webvr_traits = {path = "../webvr_traits"}
 webxr-api = {git = "https://github.com/servo/webxr", features = ["ipc"]}
diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index a8a19b5a40a..efa877adb17 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -60,6 +60,7 @@ use std::sync::Arc;
 use std::time::Duration;
 use style_traits::CSSPixel;
 use style_traits::SpeculativePainter;
+use webgpu::WebGPU;
 use webrender_api::units::{DeviceIntSize, DevicePixel, LayoutPixel};
 use webrender_api::{DocumentId, ExternalScrollId, ImageKey, RenderApiSender};
 use webvr_traits::{WebVREvent, WebVRMsg};
@@ -656,6 +657,8 @@ pub struct InitialScriptState {
     pub content_process_shutdown_chan: Sender<()>,
     /// A channel to the WebGL thread used in this pipeline.
     pub webgl_chan: Option<WebGLPipeline>,
+    /// A channel to the WebGPU threads.
+    pub webgpu: Option<WebGPU>,
     /// A channel to the webvr thread, if available.
     pub webvr_chan: Option<IpcSender<WebVRMsg>>,
     /// The XR device registry
diff --git a/components/servo/Cargo.toml b/components/servo/Cargo.toml
index 458ffb114a0..83f298fb96b 100644
--- a/components/servo/Cargo.toml
+++ b/components/servo/Cargo.toml
@@ -79,6 +79,7 @@ servo_url = {path = "../url"}
 sparkle = "0.1"
 style = {path = "../style", features = ["servo"]}
 style_traits = {path = "../style_traits", features = ["servo"]}
+webgpu = {path = "../webgpu"}
 webrender = {git = "https://github.com/servo/webrender"}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
 webrender_traits = {path = "../webrender_traits"}
diff --git a/components/servo/lib.rs b/components/servo/lib.rs
index d201bc2d757..811a4a002d9 100644
--- a/components/servo/lib.rs
+++ b/components/servo/lib.rs
@@ -49,6 +49,7 @@ pub use servo_geometry;
 pub use servo_url;
 pub use style;
 pub use style_traits;
+pub use webgpu;
 pub use webrender_api;
 pub use webrender_traits;
 pub use webvr;
@@ -863,6 +864,8 @@ fn create_constellation(
 
     let resource_sender = public_resource_threads.sender();
 
+    let webgpu = webgpu::WebGPU::new();
+
     let initial_state = InitialConstellationState {
         compositor_proxy,
         embedder_proxy,
@@ -877,6 +880,7 @@ fn create_constellation(
         webrender_document,
         webrender_api_sender,
         webgl_threads,
+        webgpu,
         webvr_chan,
         webxr_registry,
         glplayer_threads,
diff --git a/components/style/properties/longhands/box.mako.rs b/components/style/properties/longhands/box.mako.rs
index a68b179c4c0..b8b6cbc8c34 100644
--- a/components/style/properties/longhands/box.mako.rs
+++ b/components/style/properties/longhands/box.mako.rs
@@ -63,6 +63,7 @@ ${helpers.predefined_type(
     "Float",
     "computed::Float::None",
     engines="gecko servo-2013 servo-2020",
+    servo_2020_pref="layout.2020.unimplemented",
     initial_specified_value="specified::Float::None",
     spec="https://drafts.csswg.org/css-box/#propdef-float",
     animation_value_type="discrete",
diff --git a/components/style/properties/longhands/font.mako.rs b/components/style/properties/longhands/font.mako.rs
index b4b2ab0598c..7e0bff6fbbe 100644
--- a/components/style/properties/longhands/font.mako.rs
+++ b/components/style/properties/longhands/font.mako.rs
@@ -11,7 +11,6 @@ ${helpers.predefined_type(
     "font-family",
     "FontFamily",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     initial_value="computed::FontFamily::serif()",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-fonts/#propdef-font-family",
@@ -22,7 +21,6 @@ ${helpers.predefined_type(
     "font-style",
     "FontStyle",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     initial_value="computed::FontStyle::normal()",
     initial_specified_value="specified::FontStyle::normal()",
     animation_value_type="FontStyle",
@@ -40,7 +38,6 @@ ${helpers.single_keyword_system(
     "font-variant-caps",
     "normal small-caps",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     extra_gecko_values="all-small-caps petite-caps all-petite-caps unicase titling-caps",
     gecko_constant_prefix="NS_FONT_VARIANT_CAPS",
     gecko_ffi_name="mFont.variantCaps",
@@ -54,7 +51,6 @@ ${helpers.predefined_type(
     "font-weight",
     "FontWeight",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     initial_value="computed::FontWeight::normal()",
     initial_specified_value="specified::FontWeight::normal()",
     animation_value_type="Number",
@@ -97,7 +93,6 @@ ${helpers.predefined_type(
     "font-stretch",
     "FontStretch",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     initial_value="computed::FontStretch::hundred()",
     initial_specified_value="specified::FontStretch::normal()",
     animation_value_type="Percentage",
diff --git a/components/style/properties/longhands/inherited_text.mako.rs b/components/style/properties/longhands/inherited_text.mako.rs
index 18f5c466d1a..428b40a101f 100644
--- a/components/style/properties/longhands/inherited_text.mako.rs
+++ b/components/style/properties/longhands/inherited_text.mako.rs
@@ -21,7 +21,6 @@ ${helpers.predefined_type(
     "LineHeight",
     "computed::LineHeight::normal()",
     engines="gecko servo-2013 servo-2020",
-    servo_2020_pref="layout.2020.unimplemented",
     animation_value_type="LineHeight",
     spec="https://drafts.csswg.org/css2/visudet.html#propdef-line-height",
     servo_restyle_damage="reflow"
@@ -167,7 +166,7 @@ ${helpers.predefined_type(
     "letter-spacing",
     "LetterSpacing",
     "computed::LetterSpacing::normal()",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     animation_value_type="ComputedValue",
     spec="https://drafts.csswg.org/css-text/#propdef-letter-spacing",
     servo_restyle_damage="rebuild_and_reflow",
@@ -177,7 +176,7 @@ ${helpers.predefined_type(
     "word-spacing",
     "WordSpacing",
     "computed::WordSpacing::zero()",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     animation_value_type="ComputedValue",
     spec="https://drafts.csswg.org/css-text/#propdef-word-spacing",
     servo_restyle_damage="rebuild_and_reflow",
@@ -360,7 +359,7 @@ ${helpers.single_keyword(
 ${helpers.single_keyword(
     "text-rendering",
     "auto optimizespeed optimizelegibility geometricprecision",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     gecko_enum_prefix="StyleTextRendering",
     animation_value_type="discrete",
     spec="https://www.w3.org/TR/SVG11/painting.html#TextRenderingProperty",
diff --git a/components/style/properties/shorthands/font.mako.rs b/components/style/properties/shorthands/font.mako.rs
index e3b44d86a36..1feed113875 100644
--- a/components/style/properties/shorthands/font.mako.rs
+++ b/components/style/properties/shorthands/font.mako.rs
@@ -8,7 +8,6 @@
 <%helpers:shorthand
     name="font"
     engines="gecko servo-2013 servo-2020"
-    servo_2020_pref="layout.2020.unimplemented"
     sub_properties="
         font-style
         font-variant-caps
diff --git a/components/webgpu/Cargo.toml b/components/webgpu/Cargo.toml
new file mode 100644
index 00000000000..7581cf768bd
--- /dev/null
+++ b/components/webgpu/Cargo.toml
@@ -0,0 +1,20 @@
+[package]
+name = "webgpu"
+version = "0.0.1"
+authors = ["The Servo Project Developers"]
+license = "MPL-2.0"
+edition = "2018"
+publish = false
+
+[lib]
+name = "webgpu"
+path = "lib.rs"
+
+[dependencies]
+embedder_traits = {path = "../embedder_traits"}
+ipc-channel = "0.12"
+log = "0.4"
+malloc_size_of = { path = "../malloc_size_of" }
+serde = "1.0"
+servo_config = {path = "../config"}
+wgpu-native = { version = "0.4.0", features = ["serde"] }
diff --git a/components/webgpu/lib.rs b/components/webgpu/lib.rs
new file mode 100644
index 00000000000..5cb449c6c3c
--- /dev/null
+++ b/components/webgpu/lib.rs
@@ -0,0 +1,153 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#[macro_use]
+extern crate log;
+#[macro_use]
+extern crate serde;
+#[macro_use]
+pub extern crate wgpu_native as wgpu;
+
+use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
+use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
+use servo_config::pref;
+use wgpu::adapter_get_info;
+use wgpu::TypedId;
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebGPUResponse {
+    RequestAdapter(String, WebGPUAdapter),
+    RequestDevice,
+}
+
+pub type WebGPUResponseResult = Result<WebGPUResponse, String>;
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebGPURequest {
+    RequestAdapter(IpcSender<WebGPUResponseResult>, wgpu::RequestAdapterOptions),
+    RequestDevice,
+    Exit(IpcSender<()>),
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct WebGPU(pub IpcSender<WebGPURequest>);
+
+impl WebGPU {
+    pub fn new() -> Option<Self> {
+        if !pref!(dom.webgpu.enabled) {
+            return None;
+        }
+        let (sender, receiver) = match ipc::channel() {
+            Ok(sender_and_receiver) => sender_and_receiver,
+            Err(e) => {
+                warn!(
+                    "Failed to create sender and receiciver for WGPU thread ({})",
+                    e
+                );
+                return None;
+            },
+        };
+
+        if let Err(e) = std::thread::Builder::new()
+            .name("WGPU".to_owned())
+            .spawn(move || {
+                WGPU::new(receiver).run();
+            })
+        {
+            warn!("Failed to spwan WGPU thread ({})", e);
+            return None;
+        }
+        Some(WebGPU(sender))
+    }
+
+    pub fn exit(&self, sender: IpcSender<()>) -> Result<(), &'static str> {
+        self.0
+            .send(WebGPURequest::Exit(sender))
+            .map_err(|_| "Failed to send Exit message")
+    }
+}
+
+struct WGPU {
+    receiver: IpcReceiver<WebGPURequest>,
+    global: wgpu::Global,
+    adapters: Vec<WebGPUAdapter>,
+    // Track invalid adapters https://gpuweb.github.io/gpuweb/#invalid
+    _invalid_adapters: Vec<WebGPUAdapter>,
+}
+
+impl WGPU {
+    fn new(receiver: IpcReceiver<WebGPURequest>) -> Self {
+        WGPU {
+            receiver,
+            global: wgpu::Global::new("webgpu-native"),
+            adapters: Vec::new(),
+            _invalid_adapters: Vec::new(),
+        }
+    }
+
+    fn deinit(self) {
+        self.global.delete()
+    }
+
+    fn run(mut self) {
+        while let Ok(msg) = self.receiver.recv() {
+            match msg {
+                WebGPURequest::RequestAdapter(sender, options) => {
+                    let adapter_id = match wgpu::request_adapter(
+                        &self.global,
+                        &options,
+                        // TODO: The ids we pass here should be generated by the client
+                        &[
+                            wgpu::Id::zip(0, 0, wgpu::Backend::Vulkan),
+                            wgpu::Id::zip(0, 0, wgpu::Backend::Metal),
+                            wgpu::Id::zip(0, 0, wgpu::Backend::Dx12),
+                        ],
+                    ) {
+                        Some(id) => id,
+                        None => {
+                            if let Err(e) =
+                                sender.send(Err("Failed to get webgpu adapter".to_string()))
+                            {
+                                warn!(
+                                    "Failed to send response to WebGPURequest::RequestAdapter ({})",
+                                    e
+                                )
+                            }
+                            return;
+                        },
+                    };
+                    let adapter = WebGPUAdapter(adapter_id);
+                    self.adapters.push(adapter);
+                    let info =
+                        gfx_select!(adapter_id => adapter_get_info(&self.global, adapter_id));
+                    if let Err(e) =
+                        sender.send(Ok(WebGPUResponse::RequestAdapter(info.name, adapter)))
+                    {
+                        warn!(
+                            "Failed to send response to WebGPURequest::RequestAdapter ({})",
+                            e
+                        )
+                    }
+                },
+                WebGPURequest::RequestDevice => {},
+                WebGPURequest::Exit(sender) => {
+                    self.deinit();
+                    if let Err(e) = sender.send(()) {
+                        warn!("Failed to send response to WebGPURequest::Exit ({})", e)
+                    }
+                    return;
+                },
+            }
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
+pub struct WebGPUAdapter(pub wgpu::AdapterId);
+
+impl MallocSizeOf for WebGPUAdapter {
+    fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
+        0
+    }
+}
diff --git a/docs/ORGANIZATION.md b/docs/ORGANIZATION.md
index 2ec15f28b1c..d369a0b50b3 100644
--- a/docs/ORGANIZATION.md
+++ b/docs/ORGANIZATION.md
@@ -54,6 +54,8 @@
     * assorted utility methods and types that are commonly used throughout the project.
   * webdriver_server
     * In-process server to allow manipulating browser instances via a WebDriver client.
+  * webgpu
+    * Implementation of threads for the WebGPU API.
 * etc
   * Useful tools and scripts for developers.
 * mach
diff --git a/python/tidy/servo_tidy/tidy.py b/python/tidy/servo_tidy/tidy.py
index f14112df5da..d2840cc884c 100644
--- a/python/tidy/servo_tidy/tidy.py
+++ b/python/tidy/servo_tidy/tidy.py
@@ -100,6 +100,7 @@ WEBIDL_STANDARDS = [
     "//webaudio.github.io",
     "//immersive-web.github.io/",
     "//github.com/immersive-web/webxr-test-api/",
+    "//gpuweb.github.io",
     # Not a URL
     "// This interface is entirely internal to Servo, and should not be" +
     " accessible to\n// web pages."
diff --git a/resources/prefs.json b/resources/prefs.json
index d715ffab76f..8d5cd69c407 100644
--- a/resources/prefs.json
+++ b/resources/prefs.json
@@ -26,6 +26,7 @@
   "dom.testing.htmlinputelement.select_files.enabled": false,
   "dom.webgl.dom_to_texture.enabled": false,
   "dom.webgl2.enabled": false,
+  "dom.webgpu.enabled": false,
   "dom.webrtc.enabled": false,
   "dom.webvr.enabled": false,
   "dom.webvr.event_polling_interval": 500,
diff --git a/servo-tidy.toml b/servo-tidy.toml
index 46181a8bf54..71f9fb08e36 100644
--- a/servo-tidy.toml
+++ b/servo-tidy.toml
@@ -27,6 +27,7 @@ rand = [
 [ignore]
 # Ignored packages with duplicated versions
 packages = [
+  "arrayvec",
   "cgl",
   "cocoa",
   "gleam",
diff --git a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
index a9e46713244..76b398963ae 100644
--- a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
+++ b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
@@ -7,7 +7,7 @@
     expected: FAIL
 
   [Opening a blob URL in a new window immediately before revoking it works.]
-    expected: TIMEOUT
+    expected: FAIL
 
   [Opening a blob URL in a noopener about:blank window immediately before revoking it works.]
     expected: FAIL
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 3bf07accd5a..85c96a326f6 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -206661,6 +206661,30 @@
      {}
     ]
    ],
+   "quirks/percentage-height-quirk-excludes-flex-grid-001.html": [
+    [
+     "quirks/percentage-height-quirk-excludes-flex-grid-001.html",
+     [
+      [
+       "/quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
+   "quirks/percentage-height-quirk-excludes-flex-grid-002.html": [
+    [
+     "quirks/percentage-height-quirk-excludes-flex-grid-002.html",
+     [
+      [
+       "/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
    "quirks/table-cell-width-calculation-abspos.html": [
     [
      "quirks/table-cell-width-calculation-abspos.html",
@@ -212784,6 +212808,18 @@
      ],
      {}
     ]
+   ],
+   "quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html": [
+    [
+     "quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html",
+     [
+      [
+       "/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html",
+       "!="
+      ]
+     ],
+     {}
+    ]
    ]
   },
   "support": {
@@ -279057,6 +279093,12 @@
    "quirks/reference/green-100px-square-no-red.html": [
     []
    ],
+   "quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html": [
+    []
+   ],
+   "quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html": [
+    []
+   ],
    "quirks/reference/table-cell-width-calculation-abspos-ref.html": [
     []
    ],
@@ -657627,7 +657669,7 @@
    "support"
   ],
   "html/semantics/forms/form-submission-0/form-submission-algorithm.html": [
-   "df39b57353c67ebb02014865f28d739bbf24c690",
+   "2d5ac276374370dd594d3d8f98c1b85e8186eb26",
    "testharness"
   ],
   "html/semantics/forms/form-submission-0/getactionurl.html": [
@@ -680954,10 +680996,30 @@
    "e56a03b4b41b72edca91ff261e766fc9d2cc5426",
    "testharness"
   ],
+  "quirks/percentage-height-quirk-excludes-flex-grid-001.html": [
+   "cb0f772b1fa2fed26992f288cc345e7ab418d919",
+   "reftest"
+  ],
+  "quirks/percentage-height-quirk-excludes-flex-grid-002.html": [
+   "88df89d0932e8f347ffad8faa4e5da9dc2e71b56",
+   "reftest"
+  ],
   "quirks/reference/green-100px-square-no-red.html": [
    "159d9a52a01a0b328680a530603cb496ab2d5fcf",
    "support"
   ],
+  "quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html": [
+   "29f8e26a67f27e9ae250e464c05a8f3af1e0b9a5",
+   "support"
+  ],
+  "quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html": [
+   "19aa243a0045f4378b55a00dd3b2431fc9a9ec23",
+   "support"
+  ],
+  "quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html": [
+   "c63bc0efa85f59eb496875072970016cf77d3c9d",
+   "reftest_node"
+  ],
   "quirks/reference/table-cell-width-calculation-abspos-ref.html": [
    "41d2203b4a08323a2d6b9894f1ad133e35130265",
    "support"
diff --git a/tests/wpt/metadata/css/css-transforms/animation/perspective-interpolation.html.ini b/tests/wpt/metadata/css/css-transforms/animation/perspective-interpolation.html.ini
index 1193e3dfa5c..03f2f3fe9d1 100644
--- a/tests/wpt/metadata/css/css-transforms/animation/perspective-interpolation.html.ini
+++ b/tests/wpt/metadata/css/css-transforms/animation/perspective-interpolation.html.ini
@@ -1,5 +1,5 @@
 [perspective-interpolation.html]
-  expected: ERROR
+  expected: CRASH
   [ perspective interpolation]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/css/cssom-view/elementFromPoint-list-001.html.ini b/tests/wpt/metadata/css/cssom-view/elementFromPoint-list-001.html.ini
index c364dd10b5c..668c3f52a5b 100644
--- a/tests/wpt/metadata/css/cssom-view/elementFromPoint-list-001.html.ini
+++ b/tests/wpt/metadata/css/cssom-view/elementFromPoint-list-001.html.ini
@@ -14,6 +14,3 @@
   [<li>Outside 3</li>]
     expected: FAIL
 
-  [<li>Inside 1</li>]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/encoding/single-byte-decoder.html.ini b/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
index 3d135f3bd66..939a36eb9d9 100644
--- a/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
+++ b/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
@@ -2,7 +2,6 @@
   type: testharness
 
 [single-byte-decoder.html?document]
-  expected: TIMEOUT
   [ISO-8859-4: iso_8859-4:1988 (document.characterSet and document.inputEncoding)]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/fetch/content-type/response.window.js.ini b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
index 284ea0dcf02..9abfe827b60 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -312,24 +312,18 @@
   [<iframe>: combined response Content-Type: */* text/html]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html */*]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html;" text/plain]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
-    expected: FAIL
-
-  [<iframe>: separate response Content-Type: text/html */*;charset=gbk]
+  [<iframe>: separate response Content-Type: text/plain */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/html */*]
+  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*]
+  [<iframe>: combined response Content-Type: text/html;" \\" text/plain]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+  [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/fetch/content-type/script.window.js.ini b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
index d2df9b78483..e67f0406fc3 100644
--- a/tests/wpt/metadata/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
@@ -53,6 +53,3 @@
   [combined text/javascript ]
     expected: FAIL
 
-  [separate text/javascript x/x]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
index b7052af5b5c..87c807a49ff 100644
--- a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,6 +11,3 @@
   [X-Content-Type-Options%3A%20nosniff%0C]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%0D%0AX-Content-Type-Options%3A%20nosniff]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
deleted file mode 100644
index dc2e45516de..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_5.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/creating_browsing_context_test_01.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/creating_browsing_context_test_01.html.ini
deleted file mode 100644
index 16fa2c5cfc1..00000000000
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/creating_browsing_context_test_01.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[creating_browsing_context_test_01.html]
-  [first argument: absolute url]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
index bf50d59df41..e02f179ec25 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-innerwidth-innerheight.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for legacy `innerwidth`, `innerheight`]
     expected: FAIL
 
+  [features "innerheight=-404.5" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404.5" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=-404e1" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=-404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404e1" should NOT set "width=404"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
index ad8840fbb68..940516ddd33 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-top-left.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for `top`, `left`]
     expected: FAIL
 
+  [features "top=-204" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "top=-204.5" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "left=-204" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "top=-0" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "left=-204.5" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "left=-0" should NOT set "left=204"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
index 9027336b453..d1ed9088b2b 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
@@ -1,24 +1,5 @@
 [open-features-negative-width-height.html]
   type: testharness
-  expected: TIMEOUT
   [HTML: window.open `features`: negative values for `width`, `height`]
     expected: FAIL
 
-  [features "height=-404" should NOT set "height=404"]
-    expected: TIMEOUT
-
-  [features "height=-404e1" should NOT set "height=404"]
-    expected: TIMEOUT
-
-  [features "height=-404.5" should NOT set "height=404"]
-    expected: TIMEOUT
-
-  [features "width=-404" should NOT set "width=404"]
-    expected: TIMEOUT
-
-  [features "width=-404e1" should NOT set "width=404"]
-    expected: TIMEOUT
-
-  [features "width=-404.5" should NOT set "width=404"]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
index 10f617db69e..8540f53d8d6 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-top.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `top`]
     expected: FAIL
 
   [features "top=105/5" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105*3" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105LLl" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105e-1" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105.32" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105e1" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105  " should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105^4" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105.5" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "top=/104" should NOT set "top=104"]
+    expected: TIMEOUT
+
+  [features "top=_104" should NOT set "top=104"]
+    expected: TIMEOUT
+
+  [features "top=L104" should NOT set "top=104"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
index 28f93ee71b5..9d841e61bc0 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
@@ -1,32 +1,48 @@
 [open-features-non-integer-width.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `width`]
     expected: FAIL
 
   [features "width=405^4" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405.5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405e1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405  " should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405.32" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405LLl" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405*3" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405e-1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405/5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [top=0,left=0: absence of feature "width" should be treated same as "width=0"]
+    expected: TIMEOUT
+
+  [features "width=_404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [top=0,left=0,height=401,: absence of feature "width" should be treated same as "width=0"]
+    expected: TIMEOUT
+
+  [features "width=/404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "width=L404" should NOT set "width=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini b/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
index 2532dceabac..fd369192a02 100644
--- a/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
+++ b/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
@@ -1,5 +1,5 @@
 [embedded-opener-remove-frame.html]
-  expected: CRASH
+  expected: TIMEOUT
   [opener and "removed" embedded documents]
     expected: FAIL
 
@@ -7,5 +7,5 @@
     expected: FAIL
 
   [opener of discarded auxiliary browsing context]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/dom/idlharness.https.html.ini b/tests/wpt/metadata/html/dom/idlharness.https.html.ini
index 5459bedf48d..692dc849677 100644
--- a/tests/wpt/metadata/html/dom/idlharness.https.html.ini
+++ b/tests/wpt/metadata/html/dom/idlharness.https.html.ini
@@ -1409,9 +1409,6 @@
   [SubmitEvent interface: existence and properties of interface prototype object's "constructor" property]
     expected: FAIL
 
-  [FormDataEvent interface object length]
-    expected: FAIL
-
 
 [idlharness.https.html?include=(Document|Window)]
   [Document interface: documentWithHandlers must inherit property "queryCommandEnabled(DOMString)" with the proper type]
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 9df1ac56f2a..963d4cd20ef 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
@@ -1,6 +1,6 @@
 [iframe_sandbox_popups_nonescaping-1.html]
   type: testharness
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
new file mode 100644
index 00000000000..8cc42056d34
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
@@ -0,0 +1,10 @@
+[non-active-document.html]
+  [DOMParser]
+    expected: FAIL
+
+  [createHTMLDocument]
+    expected: FAIL
+
+  [<template>]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit-3.html.ini b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit-3.html.ini
index df89cd21511..941d0dee0c8 100644
--- a/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit-3.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit-3.html.ini
@@ -1,5 +1,5 @@
 [form-double-submit-3.html]
   expected: ERROR
   [<button> should have the same double-submit protection as <input type=submit>]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini
index dce74c6dd71..47a7bbb7975 100644
--- a/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini
@@ -1,5 +1,5 @@
 [form-double-submit.html]
   expected: ERROR
   [default submit action should supersede onclick submit()]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/script-onerror-insertion-point-2.html.ini b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/script-onerror-insertion-point-2.html.ini
new file mode 100644
index 00000000000..178680e5d14
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/script-onerror-insertion-point-2.html.ini
@@ -0,0 +1,2 @@
+[script-onerror-insertion-point-2.html]
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events-onerror.html.ini b/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events-onerror.html.ini
new file mode 100644
index 00000000000..1e9b11d3487
--- /dev/null
+++ b/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events-onerror.html.ini
@@ -0,0 +1,5 @@
+[promise-rejection-events-onerror.html]
+  expected: TIMEOUT
+  [Throwing inside an unhandledrejection handler invokes the error handler.]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/quirks/percentage-height-quirk-excludes-flex-grid-002.html.ini b/tests/wpt/metadata/quirks/percentage-height-quirk-excludes-flex-grid-002.html.ini
new file mode 100644
index 00000000000..cb37c253dd0
--- /dev/null
+++ b/tests/wpt/metadata/quirks/percentage-height-quirk-excludes-flex-grid-002.html.ini
@@ -0,0 +1,2 @@
+[percentage-height-quirk-excludes-flex-grid-002.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata/webmessaging/with-ports/018.html.ini b/tests/wpt/metadata/webmessaging/with-ports/018.html.ini
new file mode 100644
index 00000000000..663a1f8fa30
--- /dev/null
+++ b/tests/wpt/metadata/webmessaging/with-ports/018.html.ini
@@ -0,0 +1,5 @@
+[018.html]
+  expected: TIMEOUT
+  [origin of the script that invoked the method, javascript:]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/webmessaging/without-ports/017.html.ini b/tests/wpt/metadata/webmessaging/without-ports/017.html.ini
new file mode 100644
index 00000000000..064cf47545b
--- /dev/null
+++ b/tests/wpt/metadata/webmessaging/without-ports/017.html.ini
@@ -0,0 +1,5 @@
+[017.html]
+  expected: TIMEOUT
+  [origin of the script that invoked the method, about:blank]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/form-submission-algorithm.html b/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/form-submission-algorithm.html
index df39b57353c..2d5ac276374 100644
--- a/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/form-submission-algorithm.html
+++ b/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/form-submission-algorithm.html
@@ -18,6 +18,21 @@ test(() => {
   assert_equals(counter, 2);
 }, 'If constructing entry list flag of form is true, then return');
 
+test(() => {
+  let form = populateForm('<input><input type=submit>');
+  let submitter1 = form.querySelector('input[type=submit]');
+  let valid = form.elements[0];
+  let counter = 0;
+  valid.oninvalid = () => {
+    ++counter;
+  };
+  form.onsubmit = () => {
+    valid.required = true;
+    submitter1.dispatchEvent(new MouseEvent("click"));
+  };
+  submitter1.dispatchEvent(new MouseEvent("click"));
+  assert_equals(counter, 0);
+}, "If firing submission events flag of form is true, then return");
 
 test(() => {
   let form = populateForm('<input required><input type=submit><button type=submit></button>');
diff --git a/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-001.html b/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-001.html
new file mode 100644
index 00000000000..cb0f772b1fa
--- /dev/null
+++ b/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-001.html
@@ -0,0 +1,78 @@
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test: Percent height quirk does not traverse flex/grid containers</title>
+  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+  <link rel="author" href="https://mozilla.org" title="Mozilla">
+  <link rel="help" href="https://quirks.spec.whatwg.org/#the-percentage-height-calculation-quirk">
+  <link rel="match" href="reference/percentage-height-quirk-excludes-flex-grid-001-ref.html">
+  <meta name="assert" content="This quirk is specific to block boxes and table wrapper boxes; if it hits another type of box, it doesn't traverse further. So this file should look the same whether in quirks or standards mode.">
+  <style>
+    .fixed-height-outer {
+      height: 80px;
+      border: 1px solid gray;
+      margin-bottom: 5px;
+    }
+
+    .row-flex {
+      display: flex;
+      flex-direction: row
+    }
+
+    .column-flex {
+      display: flex;
+      flex-direction: column
+    }
+
+    .grid {
+      display: grid;
+    }
+
+    .container {
+      border: 3px solid black;
+    }
+
+    .pct {
+        height: 75%;
+        min-height: 10px;
+        width: 50px;
+        display: inline-block;
+        vertical-align: top;
+        background: purple;
+    }
+    .px {
+        height: 50px;
+        width: 50px;
+        display: inline-block;
+        vertical-align: top;
+        background: blue
+    }
+  </style>
+</head>
+<body>
+  <div class="fixed-height-outer">
+    <div class="container column-flex">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="container row-flex">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="container grid">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-002.html b/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-002.html
new file mode 100644
index 00000000000..88df89d0932
--- /dev/null
+++ b/tests/wpt/web-platform-tests/quirks/percentage-height-quirk-excludes-flex-grid-002.html
@@ -0,0 +1,56 @@
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test: Percent height quirk applies for percent heights on flex/grid containers</title>
+  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+  <link rel="author" href="https://mozilla.org" title="Mozilla">
+  <link rel="help" href="https://quirks.spec.whatwg.org/#the-percentage-height-calculation-quirk">
+  <link rel="match" href="reference/percentage-height-quirk-excludes-flex-grid-002-ref.html">
+  <meta name="assert" content="This quirk only starts differentiating by box-type when looking at the containing block of the percent-height thing. So, the quirk applies to percent-heights on flex/grid containers, when the ancestors are all blocks up to the nearest definite height.">
+  <style>
+    .fixed-height-outer {
+      height: 80px;
+      border: 1px solid gray;
+      margin-bottom: 5px;
+    }
+
+    .row-flex {
+      display: flex;
+      flex-direction: row
+    }
+
+    .column-flex {
+      display: flex;
+      flex-direction: column
+    }
+
+    .grid {
+      display: grid;
+    }
+
+    .pct {
+        height: 75%;
+        min-height: 10px;
+        width: 50px;
+        background: purple;
+    }
+  </style>
+</head>
+<body>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="column-flex pct"></div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="row-flex pct"></div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="grid pct"></div>
+    </div>
+  </div>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html
new file mode 100644
index 00000000000..29f8e26a67f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-001-ref.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Reference: Percent height quirk does not traverse flex/grid containers</title>
+  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+  <link rel="author" href="https://mozilla.org" title="Mozilla">
+  <style>
+    .fixed-height-outer {
+      height: 80px;
+      border: 1px solid gray;
+      margin-bottom: 5px;
+    }
+
+    .row-flex {
+      display: flex;
+      flex-direction: row
+    }
+
+    .column-flex {
+      display: flex;
+      flex-direction: column
+    }
+
+    .grid {
+      display: grid;
+    }
+
+    .container {
+      border: 3px solid black;
+    }
+
+    .pct {
+        height: 75%;
+        min-height: 10px;
+        width: 50px;
+        display: inline-block;
+        vertical-align: top;
+        background: purple;
+    }
+    .px {
+        height: 50px;
+        width: 50px;
+        display: inline-block;
+        vertical-align: top;
+        background: blue
+    }
+  </style>
+</head>
+<body>
+  <div class="fixed-height-outer">
+    <div class="container column-flex">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="container row-flex">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="container grid">
+      <div>
+        <div class="pct"></div>
+        <div class="px"></div>
+      </div>
+    </div>
+  </div>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html
new file mode 100644
index 00000000000..19aa243a004
--- /dev/null
+++ b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-notref.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Not-reference case: Percent height quirk applies for percent heights on flex/grid containers</title>
+  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+  <link rel="author" href="https://mozilla.org" title="Mozilla">
+  <style>
+    .fixed-height-outer {
+      height: 80px;
+      border: 1px solid gray;
+      margin-bottom: 5px;
+    }
+
+    .row-flex {
+      display: flex;
+      flex-direction: row
+    }
+
+    .column-flex {
+      display: flex;
+      flex-direction: column
+    }
+
+    .grid {
+      display: grid;
+    }
+
+    .pct {
+        height: 75%;
+        min-height: 10px;
+        width: 50px;
+        background: purple;
+    }
+  </style>
+</head>
+<body>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="column-flex pct"></div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="row-flex pct"></div>
+    </div>
+  </div>
+  <div class="fixed-height-outer">
+    <div>
+      <div class="grid pct"></div>
+    </div>
+  </div>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html
new file mode 100644
index 00000000000..c63bc0efa85
--- /dev/null
+++ b/tests/wpt/web-platform-tests/quirks/reference/percentage-height-quirk-excludes-flex-grid-002-ref.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Reference case: Percent height quirk applies for percent heights on flex/grid containers</title>
+  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+  <link rel="author" href="https://mozilla.org" title="Mozilla">
+  <link rel="mismatch" href="percentage-height-quirk-excludes-flex-grid-002-notref.html">
+  <style>
+    .fixed-height-outer {
+      height: 80px;
+      border: 1px solid gray;
+      margin-bottom: 5px;
+    }
+
+    .row-flex {
+      display: flex;
+      flex-direction: row
+    }
+
+    .column-flex {
+      display: flex;
+      flex-direction: column
+    }
+
+    .grid {
+      display: grid;
+    }
+
+    .pct {
+        height: 75%;
+        min-height: 10px;
+        width: 50px;
+        background: purple;
+    }
+  </style>
+</head>
+<body>
+  <div class="fixed-height-outer">
+    <div class="column-flex pct"></div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="row-flex pct"></div>
+  </div>
+  <div class="fixed-height-outer">
+    <div class="grid pct"></div>
+  </div>
+</body>
+</html>