constellation: Stop assuming that the viewport is shared by all WebViews (#36312)

The `Constellation` previously held a `window_size` member, but this
assumes that all `WebView`s have the same size. This change removes that
assumption as well as making sure that all `WebView`s pass their size
and HiDIP scaling to the `Constellation` when they are created.

In addition

- `WindowSizeData` is renamed to `ViewportDetails`, as it was
holding more than just the size and it didn't necessarily correspond to
  a "window." It's used for tracking viewport data, whether for an
  `<iframe>` or the main `WebView` viewport.
- `ViewportDetails` is stored more consistently so that conceptually an
  `<iframe>` can also have its own HiDPI scaling. This isn't something
  we necessarily want, but it makes everything conceptually simpler.

The goal with this change is to work toward allowing per-`WebView` HiDPI
scaling and sizing. There are still some corresponding changes in the
compositor to make that happen, but they will in a subsequent change.

Testing: This is covered by existing tests. There should be no behavior
changes.
Fixes: This is part of #36232.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/dom/documentorshadowroot.rs

@@ -128,7 +128,7 @@ impl DocumentOrShadowRoot {
         let x = *x as f32;
         let y = *y as f32;
         let point = &Point2D::new(x, y);
-        let viewport = self.window.window_size().initial_viewport;
+        let viewport = self.window.viewport_details().size;
 
         if !has_browsing_context {
             return None;
@@ -176,7 +176,7 @@ impl DocumentOrShadowRoot {
         let x = *x as f32;
         let y = *y as f32;
         let point = &Point2D::new(x, y);
-        let viewport = self.window.window_size().initial_viewport;
+        let viewport = self.window.viewport_details().size;
 
         if !has_browsing_context {
             return vec![];

components/script/dom/element.rs

@@ -4344,7 +4344,7 @@ impl Element {
         if (in_quirks_mode && doc.GetBody().as_deref() == self.downcast::<HTMLElement>()) ||
             (!in_quirks_mode && *self.root_element() == *self)
         {
-            let viewport_dimensions = doc.window().window_size().initial_viewport.round().to_i32();
+            let viewport_dimensions = doc.window().viewport_details().size.round().to_i32();
             rect.size = Size2D::<i32>::new(viewport_dimensions.width, viewport_dimensions.height);
         }
 

components/script/dom/htmliframeelement.rs

@@ -6,8 +6,8 @@ use std::cell::Cell;
 
 use base::id::{BrowsingContextId, PipelineId, WebViewId};
 use bitflags::bitflags;
-use constellation_traits::WindowSizeData;
 use dom_struct::dom_struct;
+use embedder_traits::ViewportDetails;
 use html5ever::{LocalName, Prefix, local_name, namespace_url, ns};
 use js::rust::HandleObject;
 use net_traits::ReferrerPolicy;
@@ -196,12 +196,12 @@ impl HTMLIFrameElement {
             history_handling,
         };
 
-        let window_size = WindowSizeData {
-            initial_viewport: window
-                .get_iframe_size_if_known(browsing_context_id, can_gc)
-                .unwrap_or_default(),
-            device_pixel_ratio: window.device_pixel_ratio(),
-        };
+        let viewport_details = window
+            .get_iframe_viewport_details_if_known(browsing_context_id, can_gc)
+            .unwrap_or_else(|| ViewportDetails {
+                hidpi_scale_factor: window.device_pixel_ratio(),
+                ..Default::default()
+            });
 
         match pipeline_type {
             PipelineType::InitialAboutBlank => {
@@ -212,7 +212,7 @@ impl HTMLIFrameElement {
                     load_data: load_data.clone(),
                     old_pipeline_id,
                     sandbox: sandboxed,
-                    window_size,
+                    viewport_details,
                 };
                 window
                     .as_global_scope()
@@ -227,7 +227,7 @@ impl HTMLIFrameElement {
                     webview_id,
                     opener: None,
                     load_data,
-                    window_size,
+                    viewport_details,
                 };
 
                 self.pipeline_id.set(Some(new_pipeline_id));
@@ -239,7 +239,7 @@ impl HTMLIFrameElement {
                     load_data,
                     old_pipeline_id,
                     sandbox: sandboxed,
-                    window_size,
+                    viewport_details,
                 };
                 window
                     .as_global_scope()

components/script/dom/htmlimageelement.rs

@@ -808,8 +808,8 @@ impl HTMLImageElement {
         let device_pixel_ratio = self
             .owner_document()
             .window()
-            .window_size()
-            .device_pixel_ratio
+            .viewport_details()
+            .hidpi_scale_factor
             .get() as f64;
         for (index, image_source) in img_sources.iter().enumerate() {
             let current_den = image_source.descriptor.density.unwrap();

components/script/dom/intersectionobserver.rs

@@ -444,7 +444,7 @@ impl IntersectionObserver {
                 // > (note that this processing step can only be reached if the document is fully active).
                 // TODO: viewport should consider native scrollbar if exist. Recheck Servo's scrollbar approach.
                 document.map(|document| {
-                    let viewport = document.window().window_size().initial_viewport;
+                    let viewport = document.window().viewport_details().size;
                     Rect::from_size(Size2D::new(
                         Au::from_f32_px(viewport.width),
                         Au::from_f32_px(viewport.height),

components/script/dom/window.rs

@@ -21,7 +21,7 @@ use base64::Engine;
 #[cfg(feature = "bluetooth")]
 use bluetooth_traits::BluetoothRequest;
 use canvas_traits::webgl::WebGLChan;
-use constellation_traits::{ScrollState, WindowSizeData, WindowSizeType};
+use constellation_traits::{ScrollState, WindowSizeType};
 use crossbeam_channel::{Sender, unbounded};
 use cssparser::{Parser, ParserInput, SourceLocation};
 use devtools_traits::{ScriptToDevtoolsControlMsg, TimelineMarker, TimelineMarkerType};
@@ -29,7 +29,7 @@ use dom_struct::dom_struct;
 use embedder_traits::user_content_manager::{UserContentManager, UserScript};
 use embedder_traits::{
     AlertResponse, ConfirmResponse, EmbedderMsg, PromptResponse, SimpleDialog, Theme,
-    WebDriverJSError, WebDriverJSResult,
+    ViewportDetails, WebDriverJSError, WebDriverJSResult,
 };
 use euclid::default::{Point2D as UntypedPoint2D, Rect as UntypedRect};
 use euclid::{Point2D, Rect, Scale, Size2D, Vector2D};
@@ -257,7 +257,7 @@ pub(crate) struct Window {
 
     /// Most recent unhandled resize event, if any.
     #[no_trace]
-    unhandled_resize_event: DomRefCell<Option<(WindowSizeData, WindowSizeType)>>,
+    unhandled_resize_event: DomRefCell<Option<(ViewportDetails, WindowSizeType)>>,
 
     /// Platform theme.
     #[no_trace]
@@ -274,9 +274,9 @@ pub(crate) struct Window {
     #[ignore_malloc_size_of = "Rc<T> is hard"]
     js_runtime: DomRefCell<Option<Rc<Runtime>>>,
 
-    /// The current size of the window, in pixels.
+    /// The [`ViewportDetails`] of this [`Window`]'s frame.
     #[no_trace]
-    window_size: Cell<WindowSizeData>,
+    viewport_details: Cell<ViewportDetails>,
 
     /// A handle for communicating messages to the bluetooth thread.
     #[no_trace]
@@ -1300,9 +1300,9 @@ impl WindowMethods<crate::DomTypeHolder> for Window {
     // https://drafts.csswg.org/cssom-view/#dom-window-innerheight
     //TODO Include Scrollbar
     fn InnerHeight(&self) -> i32 {
-        self.window_size
+        self.viewport_details
             .get()
-            .initial_viewport
+            .size
             .height
             .to_i32()
             .unwrap_or(0)
@@ -1311,12 +1311,7 @@ impl WindowMethods<crate::DomTypeHolder> for Window {
     // https://drafts.csswg.org/cssom-view/#dom-window-innerwidth
     //TODO Include Scrollbar
     fn InnerWidth(&self) -> i32 {
-        self.window_size
-            .get()
-            .initial_viewport
-            .width
-            .to_i32()
-            .unwrap_or(0)
+        self.viewport_details.get().size.width.to_i32().unwrap_or(0)
     }
 
     // https://drafts.csswg.org/cssom-view/#dom-window-scrollx
@@ -1822,7 +1817,7 @@ impl Window {
 
         // Step 5 & 6
         // TODO: Remove scrollbar dimensions.
-        let viewport = self.window_size.get().initial_viewport;
+        let viewport = self.viewport_details.get().size;
 
         // Step 7 & 8
         // TODO: Consider `block-end` and `inline-end` overflow direction.
@@ -1885,7 +1880,7 @@ impl Window {
     }
 
     pub(crate) fn device_pixel_ratio(&self) -> Scale<f32, CSSPixel, DevicePixel> {
-        self.window_size.get().device_pixel_ratio
+        self.viewport_details.get().hidpi_scale_factor
     }
 
     fn client_window(&self) -> (Size2D<u32, CSSPixel>, Point2D<i32, CSSPixel>) {
@@ -1994,7 +1989,7 @@ impl Window {
             document: document.upcast::<Node>().to_trusted_node_address(),
             dirty_root,
             stylesheets_changed,
-            window_size: self.window_size.get(),
+            viewport_details: self.viewport_details.get(),
             origin: self.origin().immutable().clone(),
             reflow_goal,
             dom_count: document.dom_count(),
@@ -2050,7 +2045,7 @@ impl Window {
         let size_messages = self
             .Document()
             .iframes_mut()
-            .handle_new_iframe_sizes_after_layout(results.iframe_sizes, self.device_pixel_ratio());
+            .handle_new_iframe_sizes_after_layout(results.iframe_sizes);
         if !size_messages.is_empty() {
             self.send_to_constellation(ScriptMsg::IFrameSizes(size_messages));
         }
@@ -2364,11 +2359,11 @@ impl Window {
     /// If the given |browsing_context_id| refers to an `<iframe>` that is an element
     /// in this [`Window`] and that `<iframe>` has been laid out, return its size.
     /// Otherwise, return `None`.
-    pub(crate) fn get_iframe_size_if_known(
+    pub(crate) fn get_iframe_viewport_details_if_known(
         &self,
         browsing_context_id: BrowsingContextId,
         can_gc: CanGc,
-    ) -> Option<Size2D<f32, CSSPixel>> {
+    ) -> Option<ViewportDetails> {
         // Reflow might fail, but do a best effort to return the right size.
         self.layout_reflow(QueryMsg::InnerWindowDimensionsQuery, can_gc);
         self.Document()
@@ -2533,12 +2528,12 @@ impl Window {
         };
     }
 
-    pub(crate) fn set_window_size(&self, size: WindowSizeData) {
-        self.window_size.set(size);
+    pub(crate) fn set_viewport_details(&self, size: ViewportDetails) {
+        self.viewport_details.set(size);
     }
 
-    pub(crate) fn window_size(&self) -> WindowSizeData {
-        self.window_size.get()
+    pub(crate) fn viewport_details(&self) -> ViewportDetails {
+        self.viewport_details.get()
     }
 
     /// Handle a theme change request, triggering a reflow is any actual change occured.
@@ -2563,13 +2558,13 @@ impl Window {
         self.dom_static.windowproxy_handler
     }
 
-    pub(crate) fn add_resize_event(&self, event: WindowSizeData, event_type: WindowSizeType) {
+    pub(crate) fn add_resize_event(&self, event: ViewportDetails, event_type: WindowSizeType) {
         // Whenever we receive a new resize event we forget about all the ones that came before
         // it, to avoid unnecessary relayouts
         *self.unhandled_resize_event.borrow_mut() = Some((event, event_type))
     }
 
-    pub(crate) fn take_unhandled_resize_event(&self) -> Option<(WindowSizeData, WindowSizeType)> {
+    pub(crate) fn take_unhandled_resize_event(&self) -> Option<(ViewportDetails, WindowSizeType)> {
         self.unhandled_resize_event.borrow_mut().take()
     }
 
@@ -2685,7 +2680,7 @@ impl Window {
             return false;
         };
 
-        if self.window_size() == new_size {
+        if self.viewport_details() == new_size {
             return false;
         }
 
@@ -2693,9 +2688,9 @@ impl Window {
         debug!(
             "Resizing Window for pipeline {:?} from {:?} to {new_size:?}",
             self.pipeline_id(),
-            self.window_size(),
+            self.viewport_details(),
         );
-        self.set_window_size(new_size);
+        self.set_viewport_details(new_size);
 
         // http://dev.w3.org/csswg/cssom-view/#resizing-viewports
         if size_type == WindowSizeType::Resize {
@@ -2823,7 +2818,7 @@ impl Window {
         control_chan: IpcSender<ScriptThreadMessage>,
         pipeline_id: PipelineId,
         parent_info: Option<PipelineId>,
-        window_size: WindowSizeData,
+        viewport_details: ViewportDetails,
         origin: MutableOrigin,
         creator_url: ServoUrl,
         navigation_start: CrossProcessInstant,
@@ -2848,7 +2843,7 @@ impl Window {
 
         let initial_viewport = f32_rect_to_au_rect(UntypedRect::new(
             Point2D::zero(),
-            window_size.initial_viewport.to_untyped(),
+            viewport_details.size.to_untyped(),
         ));
 
         let win = Box::new(Self {
@@ -2894,7 +2889,7 @@ impl Window {
             bluetooth_extra_permission_data: BluetoothExtraPermissionData::new(),
             page_clip_rect: Cell::new(MaxRect::max_rect()),
             unhandled_resize_event: Default::default(),
-            window_size: Cell::new(window_size),
+            viewport_details: Cell::new(viewport_details),
             current_viewport: Cell::new(initial_viewport.to_untyped()),
             layout_blocker: Cell::new(LayoutBlocker::WaitingForParse),
             current_state: Cell::new(WindowState::Alive),

components/script/dom/windowproxy.rs

@@ -326,7 +326,7 @@ impl WindowProxy {
             webview_id: response.new_webview_id,
             opener: Some(self.browsing_context_id),
             load_data,
-            window_size: window.window_size(),
+            viewport_details: window.viewport_details(),
         };
         ScriptThread::process_attach_layout(new_layout_info, document.origin().clone());
         // TODO: if noopener is false, copy the sessionStorage storage area of the creator origin.