Introdcue AshWindowTreeHost and move ash/chrome specific code in WTH to ash.

ui/aura/remote_window_tree_host_win.h

Index: ui/aura/remote_window_tree_host_win.h
diff --git a/ui/aura/remote_window_tree_host_win.h b/ui/aura/remote_window_tree_host_win.h
index c8739637889468597bd6517b84c14b6272769fab..53dff3d1c24eb02a3f6c98d08bd8bf73130b05ec 100644
--- a/ui/aura/remote_window_tree_host_win.h
+++ b/ui/aura/remote_window_tree_host_win.h
@@ -219,17 +219,12 @@ class AURA_EXPORT RemoteWindowTreeHostWin
   virtual gfx::AcceleratedWidget GetAcceleratedWidget() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void Hide() OVERRIDE;
-  virtual void ToggleFullScreen() OVERRIDE;
   virtual gfx::Rect GetBounds() const OVERRIDE;
   virtual void SetBounds(const gfx::Rect& bounds) OVERRIDE;
-  virtual gfx::Insets GetInsets() const OVERRIDE;
-  virtual void SetInsets(const gfx::Insets& insets) OVERRIDE;
   virtual gfx::Point GetLocationOnNativeScreen() const OVERRIDE;
   virtual void SetCapture() OVERRIDE;
   virtual void ReleaseCapture() OVERRIDE;
   virtual bool QueryMouseLocation(gfx::Point* location_return) OVERRIDE;
-  virtual bool ConfineCursorToRootWindow() OVERRIDE;
-  virtual void UnConfineCursor() OVERRIDE;
   virtual void PostNativeEvent(const base::NativeEvent& native_event) OVERRIDE;
   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE;
   virtual void SetCursorNative(gfx::NativeCursor cursor) OVERRIDE;