Change ui::wm::Shadow to pass ImageSkia instead of SkBitmap.

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index bcdbd4cf3a184cdee2d987ce509e440dde735555..b446e16cead1760b27cf804aa831c6cf56fe9901 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -28,6 +28,7 @@
 #include "ui/compositor/layer_delegate.h"
 #include "ui/compositor/layer_type.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/transform.h"
 
 class SkCanvas;
@@ -300,9 +301,9 @@ class COMPOSITOR_EXPORT Layer
   // Sets the layer's fill color.  May only be called for LAYER_SOLID_COLOR.
   void SetColor(SkColor color);
 
-  // Updates the nine patch layer's bitmap, aperture and border. May only be
+  // Updates the nine patch layer's image, aperture and border. May only be
   // called for LAYER_NINE_PATCH.
-  void UpdateNinePatchLayerBitmap(const SkBitmap& bitmap);
+  void UpdateNinePatchLayerImage(const gfx::ImageSkia& image);
   void UpdateNinePatchLayerAperture(const gfx::Rect& aperture);
   void UpdateNinePatchLayerBorder(const gfx::Rect& border);
 
@@ -512,6 +513,11 @@ class COMPOSITOR_EXPORT Layer
   // A cached copy of |Compositor::device_scale_factor()|.
   float device_scale_factor_;
 
+  // A cached copy of the nine patch layer's image and aperture.
+  // These are required for device scale factor change.
+  gfx::ImageSkia nine_patch_layer_image_;
+  gfx::Rect nine_patch_layer_aperture_;
+
   // The mailbox used by texture_layer_.
   cc::TextureMailbox mailbox_;