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

ui/keyboard/keyboard_controller.cc

Index: ui/keyboard/keyboard_controller.cc
diff --git a/ui/keyboard/keyboard_controller.cc b/ui/keyboard/keyboard_controller.cc
index 0977f892ed07456cde323c075665755a9841df80..1140999c2cce21dbeb91c7ae8bf9e89d344ed0f5 100644
--- a/ui/keyboard/keyboard_controller.cc
+++ b/ui/keyboard/keyboard_controller.cc
@@ -71,7 +71,8 @@ class KeyboardWindowDelegate : public aura::WindowDelegate {
     gfx::Rect keyboard_bounds = KeyboardBoundsFromWindowBounds(bounds_);
     mask->addRect(RectToSkRect(keyboard_bounds));
   }
-  virtual scoped_refptr<ui::Texture> CopyTexture() OVERRIDE { return NULL; }
+  virtual void DidRecreateLayer(ui::Layer* old_layer,
+                                ui::Layer* new_layer) OVERRIDE {}
 
   gfx::Rect bounds_;
   DISALLOW_COPY_AND_ASSIGN(KeyboardWindowDelegate);