Auto merge of #20884 - jdm:more-limits, r=avadacatavra

Don't forward GL parameter gets for constant limits.

This avoids IPC traffic for unchanging constants that are determined when the GL context is created. These changes require https://github.com/emilio/rust-offscreen-rendering-context/pull/123.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #20876.
- [x] There are tests for these changes

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---
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6 files changed, 38 insertions, 19 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b86211f1816..16feb52cb6d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -278,7 +278,7 @@ dependencies = [
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
- "offscreen_gl_context 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "offscreen_gl_context 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_bytes 0.10.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo_config 0.0.1",
  "webrender 0.57.2 (git+https://github.com/servo/webrender)",
@@ -297,7 +297,7 @@ dependencies = [
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "nonzero 0.0.1",
- "offscreen_gl_context 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "offscreen_gl_context 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_bytes 0.10.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo_config 0.0.1",
@@ -2036,7 +2036,7 @@ dependencies = [
 
 [[package]]
 name = "offscreen_gl_context"
-version = "0.16.0"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cgl 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2513,7 +2513,7 @@ dependencies = [
  "msg 0.0.1",
  "net_traits 0.0.1",
  "num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
- "offscreen_gl_context 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "offscreen_gl_context 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3921,7 +3921,7 @@ dependencies = [
 "checksum objc 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "877f30f37acef6749b1841cceab289707f211aecfc756553cd63976190e6cc2e"
 "checksum objc-foundation 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1add1b659e36c9607c7aab864a76c7a4c2760cd0cd2e120f3fb8b952c7e22bf9"
 "checksum objc_id 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e4730aa1c64d722db45f7ccc4113a3e2c465d018de6db4d3e7dfe031e8c8a297"
-"checksum offscreen_gl_context 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)" = "84e4be9374dd9e7caf6771b68b5e9e9a458c34ea2677b57993edada51abb0544"
+"checksum offscreen_gl_context 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4e6b463435d693894425acb2d41a28b06b418b54d57f3dabbd2c3ccbf1b5cf53"
 "checksum ogg 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7137bf02687385302f4c0aecd77cfce052b69f5b4ee937be778e125c62f67e30"
 "checksum ogg_metadata 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fc665717454399cba557c55ad226148996e9266ee291f8a37a98bb2cded0a490"
 "checksum openssl 0.9.24 (registry+https://github.com/rust-lang/crates.io-index)" = "a3605c298474a3aa69de92d21139fb5e2a81688d308262359d85cdd0d12a7985"
diff --git a/components/canvas/Cargo.toml b/components/canvas/Cargo.toml
index ffb319f6bb0..2c2a928e233 100644
--- a/components/canvas/Cargo.toml
+++ b/components/canvas/Cargo.toml
@@ -20,7 +20,7 @@ gleam = "0.5"
 ipc-channel = "0.10"
 log = "0.4"
 num-traits = "0.1.32"
-offscreen_gl_context = {version = "0.16", features = ["serde", "osmesa"]}
+offscreen_gl_context = {version = "0.17", features = ["serde", "osmesa"]}
 serde_bytes = "0.10"
 servo_config = {path = "../config"}
 webrender = {git = "https://github.com/servo/webrender"}
diff --git a/components/canvas_traits/Cargo.toml b/components/canvas_traits/Cargo.toml
index ffe498484c2..310c9e4eec7 100644
--- a/components/canvas_traits/Cargo.toml
+++ b/components/canvas_traits/Cargo.toml
@@ -18,7 +18,7 @@ lazy_static = "1"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 nonzero = {path = "../nonzero"}
-offscreen_gl_context = {version = "0.16", features = ["serde"]}
+offscreen_gl_context = {version = "0.17", features = ["serde"]}
 serde = "1.0"
 serde_bytes = "0.10"
 servo_config = {path = "../config"}
diff --git a/components/canvas_traits/webgl.rs b/components/canvas_traits/webgl.rs
index 227f3197d5f..826a1c9b851 100644
--- a/components/canvas_traits/webgl.rs
+++ b/components/canvas_traits/webgl.rs
@@ -480,16 +480,6 @@ parameters! {
             FrontFace = gl::FRONT_FACE,
             GenerateMipmapHint = gl::GENERATE_MIPMAP_HINT,
             GreenBits = gl::GREEN_BITS,
-            MaxCombinedTextureImageUnits = gl::MAX_COMBINED_TEXTURE_IMAGE_UNITS,
-            MaxCubeMapTextureSize = gl::MAX_CUBE_MAP_TEXTURE_SIZE,
-            MaxFragmentUniformVectors = gl::MAX_FRAGMENT_UNIFORM_VECTORS,
-            MaxRenderbufferSize = gl::MAX_RENDERBUFFER_SIZE,
-            MaxTextureImageUnits = gl::MAX_TEXTURE_IMAGE_UNITS,
-            MaxTextureSize = gl::MAX_TEXTURE_SIZE,
-            MaxVaryingVectors = gl::MAX_VARYING_VECTORS,
-            MaxVertexAttribs = gl::MAX_VERTEX_ATTRIBS,
-            MaxVertexTextureImageUnits = gl::MAX_VERTEX_TEXTURE_IMAGE_UNITS,
-            MaxVertexUniformVectors = gl::MAX_VERTEX_UNIFORM_VECTORS,
             PackAlignment = gl::PACK_ALIGNMENT,
             RedBits = gl::RED_BITS,
             SampleBuffers = gl::SAMPLE_BUFFERS,
diff --git a/components/script/Cargo.toml b/components/script/Cargo.toml
index f9a4aadf6d9..e80aac49c0a 100644
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@@ -68,7 +68,7 @@ mozjs = { version = "0.7.1", features = ["promises"]}
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
 num-traits = "0.1.32"
-offscreen_gl_context = {version = "0.16", features = ["serde"]}
+offscreen_gl_context = {version = "0.17", features = ["serde"]}
 parking_lot = "0.5"
 phf = "0.7.18"
 profile_traits = {path = "../profile_traits"}
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index 85c6c981b1a..37638e36ee4 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -51,7 +51,7 @@ use euclid::Size2D;
 use fnv::FnvHashMap;
 use half::f16;
 use js::jsapi::{JSContext, JSObject, Type};
-use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UndefinedValue};
+use js::jsval::{BooleanValue, DoubleValue, Int32Value, UInt32Value, JSVal, NullValue, UndefinedValue};
 use js::rust::CustomAutoRooterGuard;
 use js::typedarray::ArrayBufferView;
 use net_traits::image::base::PixelFormat;
@@ -1337,6 +1337,35 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
             _ => {}
         }
 
+        // Handle any MAX_ parameters by retrieving the limits that were stored
+        // when this context was created.
+        let limit = match parameter {
+            constants::MAX_VERTEX_ATTRIBS =>
+                Some(self.limits.max_vertex_attribs),
+            constants::MAX_TEXTURE_SIZE =>
+                Some(self.limits.max_tex_size),
+            constants::MAX_CUBE_MAP_TEXTURE_SIZE =>
+                Some(self.limits.max_cube_map_tex_size),
+            constants::MAX_COMBINED_TEXTURE_IMAGE_UNITS =>
+                Some(self.limits.max_combined_texture_image_units),
+            constants::MAX_FRAGMENT_UNIFORM_VECTORS =>
+                Some(self.limits.max_fragment_uniform_vectors),
+            constants::MAX_RENDERBUFFER_SIZE =>
+                Some(self.limits.max_renderbuffer_size),
+            constants::MAX_TEXTURE_IMAGE_UNITS =>
+                Some(self.limits.max_texture_image_units),
+            constants::MAX_VARYING_VECTORS =>
+                Some(self.limits.max_varying_vectors),
+            constants::MAX_VERTEX_TEXTURE_IMAGE_UNITS =>
+                Some(self.limits.max_vertex_texture_image_units),
+            constants::MAX_VERTEX_UNIFORM_VECTORS =>
+                Some(self.limits.max_vertex_uniform_vectors),
+            _ => None,
+        };
+        if let Some(limit) = limit {
+            return UInt32Value(limit);
+        }
+
         if !self.extension_manager.is_get_parameter_name_enabled(parameter) {
             self.webgl_error(WebGLError::InvalidEnum);
             return NullValue();