Add the DelegatingRenderer class with its initialize path.

cc/resource_provider.h

Index: cc/resource_provider.h
diff --git a/cc/resource_provider.h b/cc/resource_provider.h
index 860c6ca3a544b4cfd6cfe699083c57fb3460f3a7..730d9b44a1584f04dd8e5050e2d762b6d33ece97 100644
--- a/cc/resource_provider.h
+++ b/cc/resource_provider.h
@@ -53,6 +53,7 @@ public:
     WebKit::WebGraphicsContext3D* graphicsContext3D();
     TextureCopier* textureCopier() const { return m_textureCopier.get(); }
     int maxTextureSize() const { return m_maxTextureSize; }
+    GLenum bestTextureFormat() const { return m_bestTextureFormat; }
     unsigned numResources() const { return m_resources.size(); }
 
     // Checks whether a resource is in use by a consumer.
@@ -289,6 +290,7 @@ private:
     scoped_ptr<TextureUploader> m_textureUploader;
     scoped_ptr<AcceleratedTextureCopier> m_textureCopier;
     int m_maxTextureSize;
+    GLenum m_bestTextureFormat;
 
     base::ThreadChecker m_threadChecker;