Make code path for bounds changes getting to renderer less brittle

content/browser/web_contents/web_contents_view_aura.h

Index: content/browser/web_contents/web_contents_view_aura.h
diff --git a/content/browser/web_contents/web_contents_view_aura.h b/content/browser/web_contents/web_contents_view_aura.h
index bccb677ec2e58646312e1e24e9a892c3ca2b2f44..349541c2648990d58511c90c0d69de65a147eaf1 100644
--- a/content/browser/web_contents/web_contents_view_aura.h
+++ b/content/browser/web_contents/web_contents_view_aura.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_AURA_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_AURA_H_
 
+#include <set>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ -14,7 +15,9 @@
 #include "content/port/browser/render_view_host_delegate_view.h"
 #include "content/port/browser/web_contents_view_port.h"
 #include "ui/aura/client/drag_drop_delegate.h"
+#include "ui/aura/root_window_observer.h"
 #include "ui/aura/window_delegate.h"
+#include "ui/aura/window_observer.h"
 #include "ui/compositor/layer_animation_observer.h"
 
 namespace aura {
@@ -33,13 +36,66 @@ class WebContentsViewDelegate;
 class WebContentsImpl;
 class WebDragDestDelegate;
 
+class WebContentsViewAuraWindowObserverDelegate {
+ public:
+  WebContentsViewAuraWindowObserverDelegate() { }
+  virtual ~WebContentsViewAuraWindowObserverDelegate() { }
+
+  virtual aura::Window* GetDelegateWindow() = 0;
+  virtual void AddDelegateWindowObserver(aura::WindowObserver* observer) = 0;
+  virtual void RemoveDelegateWindowObserver(aura::WindowObserver* observer) = 0;
+  virtual void RemoveRootWindowObserver(aura::RootWindowObserver* observer) = 0;
+  virtual void AddRootWindowObserver(aura::RootWindowObserver* observer) = 0;
+  virtual void UpdateEditingController() = 0;
+  virtual void SendScreenRects() = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WebContentsViewAuraWindowObserverDelegate);
+};
+
+// Observer class that tracks the associated window, its ancestors, and the
+// root window to make sure that screen rect are sent to the renderer when
+// ever there is the possibility of the visible bounds changing.
+class WebContentsViewAuraWindowObserver : public aura::WindowObserver,
+                                          public aura::RootWindowObserver {
+ public:
+  explicit WebContentsViewAuraWindowObserver(
+      WebContentsViewAuraWindowObserverDelegate* delegate);
+  virtual ~WebContentsViewAuraWindowObserver();
+
+  // Overridden from aura::WindowObserver:
+  virtual void OnWindowParentChanged(aura::Window* window,
+                                     aura::Window* parent) OVERRIDE;
+  virtual void OnWindowBoundsChanged(aura::Window* window,
+                                     const gfx::Rect& old_bounds,
+                                     const gfx::Rect& new_bounds) OVERRIDE;
+  virtual void OnWindowAddedToRootWindow(aura::Window* window) OVERRIDE;
+
+  virtual void OnWindowRemovingFromRootWindow(aura::Window* window) OVERRIDE;
+
+  // Overridden RootWindowObserver:
+  virtual void OnRootWindowHostMoved(const aura::RootWindow* root,
+                                     const gfx::Point& new_origin) OVERRIDE;
+
+ private:
+  std::set<aura::Window*> GenerateAncestors(aura::Window* window);
+  void AddToObserved(const std::set<aura::Window*>& windows);
+  void RemoveFromObserved(const std::set<aura::Window*>& windows);
+
+  WebContentsViewAuraWindowObserverDelegate* delegate_;
+  std::set<aura::Window*> observed_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsViewAuraWindowObserver);
+};
+
 class CONTENT_EXPORT WebContentsViewAura
     : public WebContentsViewPort,
       public RenderViewHostDelegateView,
       NON_EXPORTED_BASE(public OverscrollControllerDelegate),
       public ui::ImplicitAnimationObserver,
       public aura::WindowDelegate,
-      public aura::client::DragDropDelegate {
+      public aura::client::DragDropDelegate,
+      public WebContentsViewAuraWindowObserverDelegate {
  public:
   WebContentsViewAura(WebContentsImpl* web_contents,
                       WebContentsViewDelegate* delegate);
@@ -49,7 +105,6 @@ class CONTENT_EXPORT WebContentsViewAura
   void SetTouchEditableForTest(TouchEditableImplAura* touch_editable);
 
  private:
-  class WindowObserver;
 #if defined(OS_WIN)
   class ChildWindowObserver;
 #endif
@@ -186,13 +241,26 @@ class CONTENT_EXPORT WebContentsViewAura
   virtual void OnDragExited() OVERRIDE;
   virtual int OnPerformDrop(const ui::DropTargetEvent& event) OVERRIDE;
 
+  // Overriden from WebContentsViewAuraWindowObserverDelegate
+  virtual aura::Window* GetDelegateWindow() OVERRIDE;
+  virtual void AddDelegateWindowObserver(aura::WindowObserver* observer)
+      OVERRIDE;
+  virtual void RemoveDelegateWindowObserver(aura::WindowObserver* observer)
+      OVERRIDE;
+  virtual void RemoveRootWindowObserver(aura::RootWindowObserver* observer)
+      OVERRIDE;
+  virtual void AddRootWindowObserver(aura::RootWindowObserver* observer)
+      OVERRIDE;
+  virtual void UpdateEditingController() OVERRIDE;
+  virtual void SendScreenRects() OVERRIDE;
+
   scoped_ptr<aura::Window> window_;
 
   // The window that shows the screenshot of the history page during an
   // overscroll navigation gesture.
   scoped_ptr<aura::Window> overscroll_window_;
 
-  scoped_ptr<WindowObserver> window_observer_;
+  scoped_ptr<WebContentsViewAuraWindowObserver> window_observer_;
 #if defined(OS_WIN)
   scoped_ptr<ChildWindowObserver> child_window_observer_;
 #endif