Outside of compositor, store window size in CSS px

This fixes an issue where the CSS viewport was too large on high-DPI displays
because it was set to the window size in device pixels, instead of px.  This
patch ensures that the window size is converted from device pixels to px
before being passed to script/layout code.

The Window trait now exposes the window size in both device pixels and
density-independent screen coordinates, with clearer method names.

src/components/script/script_task.rs

@@ -34,7 +34,7 @@ use layout_interface::UntrustedNodeAddress;
 use layout_interface;
 
 use geom::point::Point2D;
-use geom::size::Size2D;
+use geom::size::TypedSize2D;
 use js::jsapi::JS_CallFunctionValue;
 use js::jsapi::{JS_SetWrapObjectCallbacks, JS_SetGCZeal, JS_DEFAULT_ZEAL_FREQ, JS_GC};
 use js::jsapi::{JSContext, JSRuntime};
@@ -49,7 +49,7 @@ use servo_msg::constellation_msg::{PipelineId, SubpageId, Failure, FailureMsg};
 use servo_msg::constellation_msg;
 use servo_net::image_cache_task::ImageCacheTask;
 use servo_net::resource_task::ResourceTask;
-use servo_util::geometry::to_frac_px;
+use servo_util::geometry::{PagePx, to_frac_px};
 use servo_util::task::send_on_failure;
 use servo_util::namespace::Null;
 use servo_util::str::DOMString;
@@ -80,13 +80,13 @@ pub enum ScriptMsg {
     /// Sends a DOM event.
     SendEventMsg(PipelineId, Event_),
     /// Window resized.  Sends a DOM event eventually, but first we combine events.
-    ResizeMsg(PipelineId, Size2D<uint>),
+    ResizeMsg(PipelineId, TypedSize2D<PagePx, f32>),
     /// Fires a JavaScript timeout.
     FireTimerMsg(PipelineId, TimerId),
     /// Notifies script that reflow is finished.
     ReflowCompleteMsg(PipelineId, uint),
     /// Notifies script that window has been resized but to not take immediate action.
-    ResizeInactiveMsg(PipelineId, Size2D<uint>),
+    ResizeInactiveMsg(PipelineId, TypedSize2D<PagePx, f32>),
     /// Notifies the script that a pipeline should be closed.
     ExitPipelineMsg(PipelineId),
     /// Notifies the script that a window associated with a particular pipeline should be closed.
@@ -145,7 +145,7 @@ pub struct Page {
     damage: Traceable<RefCell<Option<DocumentDamage>>>,
 
     /// The current size of the window, in pixels.
-    window_size: Untraceable<Cell<Size2D<uint>>>,
+    window_size: Untraceable<Cell<TypedSize2D<PagePx, f32>>>,
 
     js_info: Traceable<RefCell<Option<JSPageInfo>>>,
 
@@ -158,7 +158,7 @@ pub struct Page {
     next_subpage_id: Untraceable<Cell<SubpageId>>,
 
     /// Pending resize event, if any.
-    resize_event: Untraceable<Cell<Option<Size2D<uint>>>>,
+    resize_event: Untraceable<Cell<Option<TypedSize2D<PagePx, f32>>>>,
 
     /// Pending scroll to fragment event, if any
     fragment_node: Cell<Option<JS<Element>>>,
@@ -201,7 +201,7 @@ impl IterablePage for Rc<Page> {
 impl Page {
     fn new(id: PipelineId, subpage_id: Option<SubpageId>,
            layout_chan: LayoutChan,
-           window_size: Size2D<uint>, resource_task: ResourceTask,
+           window_size: TypedSize2D<PagePx, f32>, resource_task: ResourceTask,
            constellation_chan: ConstellationChan,
            js_context: Rc<Cx>) -> Page {
         let js_info = JSPageInfo {
@@ -609,7 +609,7 @@ impl ScriptTask {
                constellation_chan: ConstellationChan,
                resource_task: ResourceTask,
                img_cache_task: ImageCacheTask,
-               window_size: Size2D<uint>)
+               window_size: TypedSize2D<PagePx, f32>)
                -> Rc<ScriptTask> {
         let (js_runtime, js_context) = ScriptTask::new_rt_and_cx();
         let page = Page::new(id, None, layout_chan, window_size,
@@ -690,7 +690,7 @@ impl ScriptTask {
                   failure_msg: Failure,
                   resource_task: ResourceTask,
                   image_cache_task: ImageCacheTask,
-                  window_size: Size2D<uint>) {
+                  window_size: TypedSize2D<PagePx, f32>) {
         let mut builder = TaskBuilder::new().named("ScriptTask");
         let ConstellationChan(const_chan) = constellation_chan.clone();
         send_on_failure(&mut builder, FailureMsg(failure_msg), const_chan);
@@ -737,8 +737,8 @@ impl ScriptTask {
             }
         }
 
-        for (id, Size2D { width, height }) in resizes.move_iter() {
-            self.handle_event(id, ResizeEvent(width, height));
+        for (id, size) in resizes.move_iter() {
+            self.handle_event(id, ResizeEvent(size));
         }
 
         // Store new resizes, and gather all other events.
@@ -868,7 +868,7 @@ impl ScriptTask {
     }
 
     /// Window was resized, but this script was not active, so don't reflow yet
-    fn handle_resize_inactive_msg(&self, id: PipelineId, new_size: Size2D<uint>) {
+    fn handle_resize_inactive_msg(&self, id: PipelineId, new_size: TypedSize2D<PagePx, f32>) {
         let mut page = self.page.borrow_mut();
         let page = page.find(id).expect("Received resize message for PipelineId not associated
             with a page in the page tree. This is a bug.");
@@ -1063,12 +1063,12 @@ impl ScriptTask {
     /// TODO: Actually perform DOM event dispatch.
     fn handle_event(&self, pipeline_id: PipelineId, event: Event_) {
         match event {
-            ResizeEvent(new_width, new_height) => {
-                debug!("script got resize event: {:u}, {:u}", new_width, new_height);
+            ResizeEvent(new_size) => {
+                debug!("script got resize event: {:?}", new_size);
 
                 let window = {
                     let page = get_page(&*self.page.borrow(), pipeline_id);
-                    page.window_size.deref().set(Size2D(new_width, new_height));
+                    page.window_size.deref().set(new_size);
 
                     let frame = page.frame();
                     if frame.is_some() {