aura: Window should notify WindowDelegate of bounds changed if Layer cannot.

ui/aura/window.h

Index: ui/aura/window.h
diff --git a/ui/aura/window.h b/ui/aura/window.h
index 4b812cbf0ed79b16ad041b505127acb9722aae59..7133f5aa50c9f8716cc8741fa4147df0036d0863 100644
--- a/ui/aura/window.h
+++ b/ui/aura/window.h
@@ -404,6 +404,9 @@ class AURA_EXPORT Window : public ui::LayerDelegate,
   // Updates the layer name with a name based on the window's name and id.
   void UpdateLayerName(const std::string& name);
 
+  // Returns true if the mouse is currently within our bounds.
+  bool ContainsMouse();
+
 #ifndef NDEBUG
   // These methods are useful when debugging.
   std::string GetDebugInfo() const;