aura: Start using EventPrcessor interface for event dispatch.

ui/aura/root_window.h

Index: ui/aura/root_window.h
diff --git a/ui/aura/root_window.h b/ui/aura/root_window.h
index d85e1d845e6ec7059000961072da9f5e7d0443ea..e6b46d0f132f4fd4e5923dba80a5c4121a60dedb 100644
--- a/ui/aura/root_window.h
+++ b/ui/aura/root_window.h
@@ -273,6 +273,7 @@ class AURA_EXPORT RootWindow : public ui::EventProcessor,
 
   // Overridden from ui::EventProcessor:
   virtual ui::EventTarget* GetRootTarget() OVERRIDE;
+  virtual void PrepareEventForDispatch(ui::Event* event) OVERRIDE;
 
   // Overridden from ui::EventDispatcherDelegate.
   virtual bool CanDispatchToTarget(ui::EventTarget* target) OVERRIDE;
@@ -335,7 +336,6 @@ class AURA_EXPORT RootWindow : public ui::EventProcessor,
   // current mouse location.
   ui::EventDispatchDetails SynthesizeMouseMoveEvent() WARN_UNUSED_RESULT;
 
-  void DispatchHeldEventsAsync();
   void SynthesizeMouseMoveEventAsync();
 
   // Posts a task to send synthesized mouse move event if there
@@ -344,6 +344,8 @@ class AURA_EXPORT RootWindow : public ui::EventProcessor,
 
   gfx::Transform GetInverseRootTransform() const;
 
+  void PreDispatchLocatedEvent(Window* target, ui::LocatedEvent* event);
+
   // TODO(beng): evaluate the ideal ownership model.
   scoped_ptr<Window> window_;
 
@@ -378,6 +380,9 @@ class AURA_EXPORT RootWindow : public ui::EventProcessor,
   // Allowing for reposting of events. Used when exiting context menus.
   scoped_ptr<ui::LocatedEvent>  held_repostable_event_;
 
+  // Set when dispatching a held event.
+  bool dispatching_held_event_;
+
   scoped_ptr<ui::ViewProp> prop_;
 
   scoped_ptr<RootWindowTransformer> transformer_;