Auto merge of #10654 - notriddle:no_resize_on_initial_load, r=asajeffrey

compositing/script: Do not dispatch the resize event when initially l…

…oading.

No bug report corresponds to this, but I noticed it while trying to
reduce #10593

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---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10654)
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10 files changed, 103 insertions, 48 deletions

diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index 2dddffe15a9..23c7bfe2926 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -31,7 +31,7 @@ use layers::scene::Scene;
 use layout_traits::LayoutControlChan;
 use msg::constellation_msg::{ConvertPipelineIdFromWebRender, ConvertPipelineIdToWebRender, Image, PixelFormat};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
-use msg::constellation_msg::{NavigationDirection, PipelineId, WindowSizeData};
+use msg::constellation_msg::{NavigationDirection, PipelineId, WindowSizeData, WindowSizeType};
 use pipeline::CompositionPipeline;
 use profile_traits::mem::{self, ReportKind, Reporter, ReporterRequest};
 use profile_traits::time::{self, ProfilerCategory, profile};
@@ -461,7 +461,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         compositor.update_zoom_transform();
 
         // Tell the constellation about the initial window size.
-        compositor.send_window_size();
+        compositor.send_window_size(WindowSizeType::Initial);
 
         compositor
     }
@@ -822,7 +822,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
         // Initialize the new constellation channel by sending it the root window size.
         self.constellation_chan = new_constellation_chan;
-        self.send_window_size();
+        self.send_window_size(WindowSizeType::Initial);
 
         self.frame_tree_id.next();
         self.composite_if_necessary(CompositingReason::NewFrameTree);
@@ -1062,15 +1062,15 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         self.pending_subpages.insert(subpage_pipeline_id);
     }
 
-    fn send_window_size(&self) {
+    fn send_window_size(&self, size_type: WindowSizeType) {
         let dppx = self.page_zoom * self.device_pixels_per_screen_px();
         let initial_viewport = self.window_size.as_f32() / dppx;
         let visible_viewport = initial_viewport / self.viewport_zoom;
-        let msg = ConstellationMsg::ResizedWindow(WindowSizeData {
+        let msg = ConstellationMsg::WindowSize(WindowSizeData {
             device_pixel_ratio: dppx,
             initial_viewport: initial_viewport,
             visible_viewport: visible_viewport,
-        });
+        }, size_type);
 
         if let Err(e) = self.constellation_chan.send(msg) {
             warn!("Sending window resize to constellation failed ({}).", e);
@@ -1295,7 +1295,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         self.window_size = new_size;
 
         self.scene.set_root_layer_size(new_size.as_f32());
-        self.send_window_size();
+        self.send_window_size(WindowSizeType::Resize);
     }
 
     fn on_load_url_window_event(&mut self, url_string: String) {
@@ -1725,14 +1725,14 @@ impl<Window: WindowMethods> IOCompositor<Window> {
     fn on_zoom_reset_window_event(&mut self) {
         self.page_zoom = ScaleFactor::new(1.0);
         self.update_zoom_transform();
-        self.send_window_size();
+        self.send_window_size(WindowSizeType::Resize);
     }
 
     fn on_zoom_window_event(&mut self, magnification: f32) {
         self.page_zoom = ScaleFactor::new((self.page_zoom.get() * magnification)
                                           .max(MIN_ZOOM).min(MAX_ZOOM));
         self.update_zoom_transform();
-        self.send_window_size();
+        self.send_window_size(WindowSizeType::Resize);
     }
 
     /// Simulate a pinch zoom
diff --git a/components/compositing/constellation.rs b/components/compositing/constellation.rs
index 4a4aec9d8c7..cbe0af88823 100644
--- a/components/compositing/constellation.rs
+++ b/components/compositing/constellation.rs
@@ -33,7 +33,7 @@ use msg::constellation_msg::WebDriverCommandMsg;
 use msg::constellation_msg::{FrameId, PipelineId};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{PipelineNamespace, PipelineNamespaceId, NavigationDirection};
-use msg::constellation_msg::{SubpageId, WindowSizeData};
+use msg::constellation_msg::{SubpageId, WindowSizeData, WindowSizeType};
 use msg::constellation_msg::{self, ConstellationChan, PanicMsg};
 use msg::webdriver_msg;
 use net_traits::image_cache_thread::ImageCacheThread;
@@ -639,9 +639,9 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
                 debug!("constellation got navigation message from compositor");
                 self.handle_navigate_msg(pipeline_info, direction);
             }
-            Request::Compositor(FromCompositorMsg::ResizedWindow(new_size)) => {
+            Request::Compositor(FromCompositorMsg::WindowSize(new_size, size_type)) => {
                 debug!("constellation got window resize message");
-                self.handle_resized_window_msg(new_size);
+                self.handle_window_size_msg(new_size, size_type);
             }
             Request::Compositor(FromCompositorMsg::TickAnimation(pipeline_id, tick_type)) => {
                 self.handle_tick_animation(pipeline_id, tick_type)
@@ -910,7 +910,7 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             visible_viewport: *size,
             initial_viewport: *size * ScaleFactor::new(1.0),
             device_pixel_ratio: self.window_size.device_pixel_ratio,
-        });
+        }, WindowSizeType::Initial);
 
         // Store the new rect inside the pipeline
         let result = {
@@ -1581,8 +1581,8 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
     }
 
     /// Called when the window is resized.
-    fn handle_resized_window_msg(&mut self, new_size: WindowSizeData) {
-        debug!("handle_resized_window_msg: {:?} {:?}", new_size.initial_viewport.to_untyped(),
+    fn handle_window_size_msg(&mut self, new_size: WindowSizeData, size_type: WindowSizeType) {
+        debug!("handle_window_size_msg: {:?} {:?}", new_size.initial_viewport.to_untyped(),
                                                        new_size.visible_viewport.to_untyped());
 
         if let Some(root_frame_id) = self.root_frame_id {
@@ -1597,14 +1597,23 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
                 None => return warn!("Pipeline {:?} resized after closing.", pipeline_id),
                 Some(pipeline) => pipeline,
             };
-            let _ = pipeline.script_chan.send(ConstellationControlMsg::Resize(pipeline.id, new_size));
+            let _ = pipeline.script_chan.send(ConstellationControlMsg::Resize(
+                pipeline.id,
+                new_size,
+                size_type
+            ));
             for pipeline_id in frame.prev.iter().chain(&frame.next) {
                 let pipeline = match self.pipelines.get(&pipeline_id) {
-                    None => { warn!("Inactive pipeline {:?} resized after closing.", pipeline_id); continue; },
+                    None => {
+                        warn!("Inactive pipeline {:?} resized after closing.", pipeline_id);
+                        continue;
+                    },
                     Some(pipeline) => pipeline,
                 };
-                let _ = pipeline.script_chan.send(ConstellationControlMsg::ResizeInactive(pipeline.id,
-                                                                                          new_size));
+                let _ = pipeline.script_chan.send(ConstellationControlMsg::ResizeInactive(
+                    pipeline.id,
+                    new_size
+                ));
             }
         }
 
@@ -1616,8 +1625,11 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
                 Some(pipeline) => pipeline,
             };
             if pipeline.parent_info.is_none() {
-                let _ = pipeline.script_chan.send(ConstellationControlMsg::Resize(pipeline.id,
-                                                                                  new_size));
+                let _ = pipeline.script_chan.send(ConstellationControlMsg::Resize(
+                    pipeline.id,
+                    new_size,
+                    size_type
+                ));
             }
         }
 
diff --git a/components/compositing/lib.rs b/components/compositing/lib.rs
index eea4854b989..eafe95a272a 100644
--- a/components/compositing/lib.rs
+++ b/components/compositing/lib.rs
@@ -59,7 +59,7 @@ use gfx_traits::Epoch;
 use ipc_channel::ipc::{IpcSender};
 use msg::constellation_msg::{FrameId, Key, KeyState, KeyModifiers, LoadData};
 use msg::constellation_msg::{NavigationDirection, PipelineId, SubpageId};
-use msg::constellation_msg::{WebDriverCommandMsg, WindowSizeData};
+use msg::constellation_msg::{WebDriverCommandMsg, WindowSizeData, WindowSizeType};
 use std::collections::HashMap;
 use url::Url;
 
@@ -103,7 +103,7 @@ pub enum CompositorMsg {
     KeyEvent(Key, KeyState, KeyModifiers),
     LoadUrl(PipelineId, LoadData),
     Navigate(Option<(PipelineId, SubpageId)>, NavigationDirection),
-    ResizedWindow(WindowSizeData),
+    WindowSize(WindowSizeData, WindowSizeType),
     /// Requests that the constellation instruct layout to begin a new tick of the animation.
     TickAnimation(PipelineId, AnimationTickType),
     /// Dispatch a webdriver command
diff --git a/components/msg/constellation_msg.rs b/components/msg/constellation_msg.rs
index cfdcdfea1ab..51270ce95c2 100644
--- a/components/msg/constellation_msg.rs
+++ b/components/msg/constellation_msg.rs
@@ -50,6 +50,12 @@ pub struct WindowSizeData {
     pub device_pixel_ratio: ScaleFactor<ViewportPx, DevicePixel, f32>,
 }
 
+#[derive(Deserialize, Eq, PartialEq, Serialize, Copy, Clone, HeapSizeOf)]
+pub enum WindowSizeType {
+    Initial,
+    Resize,
+}
+
 #[derive(PartialEq, Eq, Copy, Clone, Debug, Deserialize, Serialize)]
 pub enum KeyState {
     Pressed,
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index b7dc3e2f663..acda028a834 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -56,7 +56,7 @@ use js::rust::Runtime;
 use layout_interface::{LayoutChan, LayoutRPC};
 use libc;
 use msg::constellation_msg::ConstellationChan;
-use msg::constellation_msg::{PipelineId, SubpageId, WindowSizeData};
+use msg::constellation_msg::{PipelineId, SubpageId, WindowSizeData, WindowSizeType};
 use net_traits::image::base::{Image, ImageMetadata};
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheThread};
 use net_traits::response::HttpsState;
@@ -294,7 +294,7 @@ no_jsmanaged_fields!(PropertyDeclarationBlock);
 no_jsmanaged_fields!(HashSet<T>);
 // These three are interdependent, if you plan to put jsmanaged data
 // in one of these make sure it is propagated properly to containing structs
-no_jsmanaged_fields!(SubpageId, WindowSizeData, PipelineId);
+no_jsmanaged_fields!(SubpageId, WindowSizeData, WindowSizeType, PipelineId);
 no_jsmanaged_fields!(TimerEventId, TimerSource);
 no_jsmanaged_fields!(WorkerId);
 no_jsmanaged_fields!(QuirksMode);
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 82bfee7e279..d5abbfbcc3a 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -43,7 +43,8 @@ use js::rust::Runtime;
 use layout_interface::{ContentBoxResponse, ContentBoxesResponse, ResolvedStyleResponse, ScriptReflow};
 use layout_interface::{LayoutChan, LayoutRPC, Msg, Reflow, ReflowQueryType, MarginStyleResponse};
 use libc;
-use msg::constellation_msg::{ConstellationChan, LoadData, PipelineId, SubpageId, WindowSizeData};
+use msg::constellation_msg::{ConstellationChan, LoadData, PipelineId, SubpageId};
+use msg::constellation_msg::{WindowSizeData, WindowSizeType};
 use msg::webdriver_msg::{WebDriverJSError, WebDriverJSResult};
 use net_traits::ResourceThread;
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheThread};
@@ -181,7 +182,7 @@ pub struct Window {
     next_subpage_id: Cell<SubpageId>,
 
     /// Pending resize event, if any.
-    resize_event: Cell<Option<WindowSizeData>>,
+    resize_event: Cell<Option<(WindowSizeData, WindowSizeType)>>,
 
     /// Pipeline id associated with this page.
     id: PipelineId,
@@ -1280,11 +1281,11 @@ impl Window {
         self.pending_reflow_count.set(self.pending_reflow_count.get() + 1);
     }
 
-    pub fn set_resize_event(&self, event: WindowSizeData) {
-        self.resize_event.set(Some(event));
+    pub fn set_resize_event(&self, event: WindowSizeData, event_type: WindowSizeType) {
+        self.resize_event.set(Some((event, event_type)));
     }
 
-    pub fn steal_resize_event(&self) -> Option<WindowSizeData> {
+    pub fn steal_resize_event(&self) -> Option<(WindowSizeData, WindowSizeType)> {
         let event = self.resize_event.get();
         self.resize_event.set(None);
         event
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index c7a6f007154..22d1ddb0206 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -61,7 +61,7 @@ use layout_interface::{self, LayoutChan, NewLayoutThreadInfo, ScriptLayoutChan};
 use mem::heap_size_of_self_and_children;
 use msg::constellation_msg::{ConstellationChan, LoadData};
 use msg::constellation_msg::{PipelineId, PipelineNamespace};
-use msg::constellation_msg::{SubpageId, WindowSizeData};
+use msg::constellation_msg::{SubpageId, WindowSizeData, WindowSizeType};
 use msg::webdriver_msg::WebDriverScriptCommand;
 use net_traits::LoadData as NetLoadData;
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread};
@@ -635,8 +635,8 @@ impl ScriptThread {
             }
         }
 
-        for (id, size) in resizes {
-            self.handle_event(id, ResizeEvent(size));
+        for (id, (size, size_type)) in resizes {
+            self.handle_event(id, ResizeEvent(size, size_type));
         }
 
         // Store new resizes, and gather all other events.
@@ -689,9 +689,9 @@ impl ScriptThread {
                         self.handle_new_layout(new_layout_info);
                     })
                 }
-                FromConstellation(ConstellationControlMsg::Resize(id, size)) => {
+                FromConstellation(ConstellationControlMsg::Resize(id, size, size_type)) => {
                     self.profile_event(ScriptThreadEventCategory::Resize, || {
-                        self.handle_resize(id, size);
+                        self.handle_resize(id, size, size_type);
                     })
                 }
                 FromConstellation(ConstellationControlMsg::Viewport(id, rect)) => {
@@ -1020,10 +1020,10 @@ impl ScriptThread {
         }
     }
 
-    fn handle_resize(&self, id: PipelineId, size: WindowSizeData) {
+    fn handle_resize(&self, id: PipelineId, size: WindowSizeData, size_type: WindowSizeType) {
         if let Some(ref page) = self.find_subpage(id) {
             let window = page.window();
-            window.set_resize_event(size);
+            window.set_resize_event(size, size_type);
             return;
         }
         let mut loads = self.incomplete_loads.borrow_mut();
@@ -1670,8 +1670,8 @@ impl ScriptThread {
         }
 
         match event {
-            ResizeEvent(new_size) => {
-                self.handle_resize_event(pipeline_id, new_size);
+            ResizeEvent(new_size, size_type) => {
+                self.handle_resize_event(pipeline_id, new_size, size_type);
             }
 
             MouseButtonEvent(event_type, button, point) => {
@@ -1831,7 +1831,7 @@ impl ScriptThread {
         }
     }
 
-    fn handle_resize_event(&self, pipeline_id: PipelineId, new_size: WindowSizeData) {
+    fn handle_resize_event(&self, pipeline_id: PipelineId, new_size: WindowSizeData, size_type: WindowSizeType) {
         let page = get_page(&self.root_page(), pipeline_id);
         let window = page.window();
         window.set_window_size(new_size);
@@ -1849,11 +1849,13 @@ impl ScriptThread {
 
         // http://dev.w3.org/csswg/cssom-view/#resizing-viewports
         // https://dvcs.w3.org/hg/dom3events/raw-file/tip/html/DOM3-Events.html#event-type-resize
-        let uievent = UIEvent::new(window.r(),
-                                   DOMString::from("resize"), EventBubbles::DoesNotBubble,
-                                   EventCancelable::NotCancelable, Some(window.r()),
-                                   0i32);
-        uievent.upcast::<Event>().fire(window.upcast());
+        if size_type == WindowSizeType::Resize {
+            let uievent = UIEvent::new(window.r(),
+                                       DOMString::from("resize"), EventBubbles::DoesNotBubble,
+                                       EventCancelable::NotCancelable, Some(window.r()),
+                                       0i32);
+            uievent.upcast::<Event>().fire(window.upcast());
+        }
     }
 
     /// Initiate a non-blocking fetch for a specified resource. Stores the InProgressLoad
diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index b8b0a34c77d..46c3e860643 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -41,7 +41,7 @@ use gfx_traits::Epoch;
 use gfx_traits::LayerId;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use libc::c_void;
-use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId, WindowSizeData};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId, WindowSizeData, WindowSizeType};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{PipelineNamespaceId, SubpageId};
 use msg::webdriver_msg::WebDriverScriptCommand;
@@ -109,7 +109,7 @@ pub enum ConstellationControlMsg {
     /// Gives a channel and ID to a layout thread, as well as the ID of that layout's parent
     AttachLayout(NewLayoutInfo),
     /// Window resized.  Sends a DOM event eventually, but first we combine events.
-    Resize(PipelineId, WindowSizeData),
+    Resize(PipelineId, WindowSizeData, WindowSizeType),
     /// Notifies script that window has been resized but to not take immediate action.
     ResizeInactive(PipelineId, WindowSizeData),
     /// Notifies the script that a pipeline should be closed.
@@ -220,7 +220,7 @@ pub enum MouseEventType {
 #[derive(Deserialize, Serialize)]
 pub enum CompositorEvent {
     /// The window was resized.
-    ResizeEvent(WindowSizeData),
+    ResizeEvent(WindowSizeData, WindowSizeType),
     /// A mouse button state changed.
     MouseButtonEvent(MouseEventType, MouseButton, Point2D<f32>),
     /// The mouse was moved over a point (or was moved out of the recognizable region).
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 98f8b14b52a..72b1a3c9946 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -6682,6 +6682,12 @@
             "url": "/_mozilla/mozilla/window_requestAnimationFrame2.html"
           }
         ],
+        "mozilla/window_resize_not_triggered_on_load.html": [
+          {
+            "path": "mozilla/window_resize_not_triggered_on_load.html",
+            "url": "/_mozilla/mozilla/window_resize_not_triggered_on_load.html"
+          }
+        ],
         "mozilla/window_setInterval.html": [
           {
             "path": "mozilla/window_setInterval.html",
diff --git a/tests/wpt/mozilla/tests/mozilla/window_resize_not_triggered_on_load.html b/tests/wpt/mozilla/tests/mozilla/window_resize_not_triggered_on_load.html
new file mode 100644
index 00000000000..f551f67ee91
--- /dev/null
+++ b/tests/wpt/mozilla/tests/mozilla/window_resize_not_triggered_on_load.html
@@ -0,0 +1,28 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org/">
+<link rel="author" title="Michael Howell" href="https://www.notriddle.com/">
+<link rel="help" href="https://drafts.csswg.org/cssom-view/#resizing-viewports">
+<script>
+<!-- This event handler needs to be registered before the first layout -->
+var resize_run = false;
+window.onresize = function() {
+    resize_run = true;
+};
+</script>
+<title>window.onresize should not be called when the window first loads</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=d></div>
+<script>
+var t = async_test("window.onresize should not be called when the window first loads");
+var d = document.getElementById("d");
+window.getComputedStyle(d, null).getPropertyValue("width");
+d.style.width = "1px";
+window.onload = function() {
+    t.step(function() {
+        assert_true(!resize_run);
+        t.done();
+    });
+};
+</script>