Update the nine patch layer to use UI resources

cc/resources/scoped_ui_resource.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_SCOPED_UI_RESOURCE_H_
 #define CC_RESOURCES_SCOPED_UI_RESOURCE_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/base/cc_export.h"
 #include "cc/resources/ui_resource_bitmap.h"
 #include "cc/resources/ui_resource_client.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
 
 class LayerTreeHost;
 
+// ScopedUIResource creates an UIResource from a bitmap and a LayerTreeHost.
+// This class holds a pointer to the host so that when the instance goes out of
+// scope, the created resource is deleted.  On a GetBitmap call from the
+// UIResource manager, ScopeUIResource always returns the reference to the
+// initially given bitmap, regardless of whether the resquest was because of
+// lost resource or not.
 class CC_EXPORT ScopedUIResource : public UIResourceClient {
  public:
   static scoped_ptr<ScopedUIResource> Create(
       LayerTreeHost* host,
       scoped_refptr<UIResourceBitmap> bitmap);
   virtual ~ScopedUIResource();
 
+  // UIResourceClient implementation.
   virtual scoped_refptr<UIResourceBitmap> GetBitmap(
       UIResourceId uid,
       bool resource_lost) OVERRIDE;
-  UIResourceId id() { return id_; }
+
+  UIResourceId id();
 
  protected:
   ScopedUIResource(LayerTreeHost* host, scoped_refptr<UIResourceBitmap> bitmap);
 
   // An empty default contructor for testing.
   ScopedUIResource();
 
   scoped_refptr<UIResourceBitmap> bitmap_;
   LayerTreeHost* host_;
   UIResourceId id_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedUIResource);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_SCOPED_UI_RESOURCE_H_