Snap RWHVA and resize the legacy window on Windows whenever the ancestor window's bounds change.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 146355707f08f247446929d5c6c0d22d7b5e11e2..f6d1b48bd5f00c74fde472733c38bf6a9fa47f71 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -334,26 +334,59 @@ void RenderWidgetHostViewAura::ApplyEventFilterForPopupExit(
 class RenderWidgetHostViewAura::WindowObserver : public aura::WindowObserver {
  public:
   explicit WindowObserver(RenderWidgetHostViewAura* view)
-      : view_(view) {
+      : view_(view),
+        view_ancestor_(nullptr) {
     view_->window_->AddObserver(this);
   }
 
-  ~WindowObserver() override { view_->window_->RemoveObserver(this); }
+  ~WindowObserver() override {
+    if (view_ancestor_)
+      view_ancestor_->RemoveObserver(this);
+    view_->window_->RemoveObserver(this);
+  }
 
   // Overridden from aura::WindowObserver:
   void OnWindowAddedToRootWindow(aura::Window* window) override {
-    if (window == view_->window_)
+    if (window == view_->window_) {
+      if (window->parent() && window->parent()->parent()) {
+        // We observe the ancestor for bounds changes and snap the RWHVA
+        // instance to pixel boundaries. Reason for doing this is there are
+        // cases like the fast resize code path for bookmarks where in the
+        // parent of RWHVA which is WCV has its bounds changed before the
+        // bookmark is hidden. This results in it reporting the old bounds
+        // which includes the bookmark. Eventually when it does get the correct
+        // bounds after the bar is hidden, the layer ignores the bounds changed
+        // call as the bounds are the same. To work around this we observe the
+        // parent of WCV for bounds changed notifications and snap when we
+        // receive them.
+        view_ancestor_ = window->parent()->parent();
+        view_ancestor_->AddObserver(this);

[sky, 2015/04/08 20:13:09]

Don't you want to know when the bounds of any ancestor changes?

[ananta, 2015/04/08 21:08:20]

Done.

+      }
       view_->AddedToRootWindow();
+    }
   }
 
   void OnWindowRemovingFromRootWindow(aura::Window* window,
                                       aura::Window* new_root) override {
-    if (window == view_->window_)
+    if (window == view_->window_) {
+      if (view_ancestor_) {
+        view_ancestor_->RemoveObserver(this);
+        view_ancestor_ = nullptr;
+      }
       view_->RemovingFromRootWindow();
+    }
+  }
+
+  void OnWindowBoundsChanged(aura::Window* window,
+                             const gfx::Rect& old_bounds,
+                             const gfx::Rect& new_bounds) override {
+    if (window == view_ancestor_)
+      view_->HandleParentBoundsChanged();
   }
 
  private:
   RenderWidgetHostViewAura* view_;
+  aura::Window* view_ancestor_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowObserver);
 };
@@ -734,6 +767,16 @@ bool RenderWidgetHostViewAura::CanRendererHandleEvent(
   return true;
 }
 
+void RenderWidgetHostViewAura::HandleParentBoundsChanged() {
+  SnapToPhysicalPixelBoundary();
+#if defined(OS_WIN)
+  if (legacy_render_widget_host_HWND_) {
+    legacy_render_widget_host_HWND_->SetBounds(
+        window_->GetBoundsInRootWindow());
+  }
+#endif
+}
+
 void RenderWidgetHostViewAura::MovePluginWindows(
     const std::vector<WebPluginGeometry>& plugin_window_moves) {
 #if defined(OS_WIN)