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..8aa0a36617997ebb318d1c892f4eb147cb3b5fe6 100644
--- a/content/browser/web_contents/web_contents_view_aura.h
+++ b/content/browser/web_contents/web_contents_view_aura.h
@@ -10,6 +10,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/renderer_host/overscroll_controller_delegate.h"
+#include "content/browser/web_contents/aura/native_view_screen_bounds_observer.h"
 #include "content/common/content_export.h"
 #include "content/port/browser/render_view_host_delegate_view.h"
 #include "content/port/browser/web_contents_view_port.h"
@@ -39,7 +40,8 @@ class CONTENT_EXPORT WebContentsViewAura
       NON_EXPORTED_BASE(public OverscrollControllerDelegate),
       public ui::ImplicitAnimationObserver,
       public aura::WindowDelegate,
-      public aura::client::DragDropDelegate {
+      public aura::client::DragDropDelegate,
+      public NativeViewScreenBoundsObserverDelegate {
  public:
   WebContentsViewAura(WebContentsImpl* web_contents,
                       WebContentsViewDelegate* delegate);
@@ -49,7 +51,6 @@ class CONTENT_EXPORT WebContentsViewAura
   void SetTouchEditableForTest(TouchEditableImplAura* touch_editable);
 
  private:
-  class WindowObserver;
 #if defined(OS_WIN)
   class ChildWindowObserver;
 #endif
@@ -186,13 +187,26 @@ class CONTENT_EXPORT WebContentsViewAura
   virtual void OnDragExited() OVERRIDE;
   virtual int OnPerformDrop(const ui::DropTargetEvent& event) OVERRIDE;
 
+  // Overriden from NativeViewScreenBoundsObserverDelegate
+  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 OnScreenPositionChanged() OVERRIDE;
+  virtual void OnScreenBoundsChanged() 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<NativeViewScreenBoundsObserver> bounds_observer_;
 #if defined(OS_WIN)
   scoped_ptr<ChildWindowObserver> child_window_observer_;
 #endif