Implement NativeViewHostAura::InstallClip.

ui/views/controls/native/native_view_host_aura.h

Index: ui/views/controls/native/native_view_host_aura.h
diff --git a/ui/views/controls/native/native_view_host_aura.h b/ui/views/controls/native/native_view_host_aura.h
index 8ef4e455f3dc414c2e485eef28c3ca92a5feafc2..08aaf27fce097b6b35e5578afacb309e34d720c3 100644
--- a/ui/views/controls/native/native_view_host_aura.h
+++ b/ui/views/controls/native/native_view_host_aura.h
@@ -7,6 +7,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/views/controls/native/native_view_host_wrapper.h"
 #include "ui/views/views_export.h"
@@ -23,7 +24,7 @@ class VIEWS_EXPORT NativeViewHostAura : public NativeViewHostWrapper,
   virtual ~NativeViewHostAura();
 
   // Overridden from NativeViewHostWrapper:
-  virtual void NativeViewWillAttach() OVERRIDE;
+  virtual void AttachNativeView() OVERRIDE;
   virtual void NativeViewDetaching(bool destroyed) OVERRIDE;
   virtual void AddedToWidget() OVERRIDE;
   virtual void RemovedFromWidget() OVERRIDE;
@@ -37,15 +38,31 @@ class VIEWS_EXPORT NativeViewHostAura : public NativeViewHostWrapper,
   virtual gfx::NativeCursor GetCursor(int x, int y) OVERRIDE;
 
  private:
+  friend class NativeViewHostAuraTest;
+
   // Overridden from aura::WindowObserver:
   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
 
+  // Reparents the native view with the clipping window existing between it and
+  // its old parent, so that the fast resize path works.
+  void AddClippingWindow();
+
+  // If the native view has been reparented via AddClippingWindow, this call
+  // undoes it.
+  void RemoveClippingWindow();
+
   // Our associated NativeViewHost.
   NativeViewHost* host_;
 
   // Have we installed a clip region?
   bool installed_clip_;
 
+  // Window that exists between the native view and the parent that allows for
+  // clipping to occur. This is positioned in the coordinate space of
+  // host_->GetWidget().
+  aura::Window clipping_window_;
+  gfx::Rect clip_rect_;
+
   DISALLOW_COPY_AND_ASSIGN(NativeViewHostAura);
 };