Move the content-dependent RecreateLayer logic from aura::Window to RWHVA

ash/drag_drop/drag_drop_controller.cc

Index: ash/drag_drop/drag_drop_controller.cc
diff --git a/ash/drag_drop/drag_drop_controller.cc b/ash/drag_drop/drag_drop_controller.cc
index 5973343584e722cea6836ba357ed2d58ec909bca..8d587c496b4b53d54a06f8b465b3726774f407d2 100644
--- a/ash/drag_drop/drag_drop_controller.cc
+++ b/ash/drag_drop/drag_drop_controller.cc
@@ -125,9 +125,8 @@ class DragDropTrackerDelegate : public aura::WindowDelegate {
   virtual void GetHitTestMask(gfx::Path* mask) const OVERRIDE {
     DCHECK(mask->isEmpty());
   }
-  virtual scoped_refptr<ui::Texture> CopyTexture() OVERRIDE {
-    return scoped_refptr<ui::Texture>();
-  }
+  virtual void DidRecreateLayer(ui::Layer* old_layer,
+                                ui::Layer* new_layer) OVERRIDE {}
 
  private:
   DragDropController* drag_drop_controller_;