[cc] Unify static create method of ResourceUpdate

cc/resources/skpicture_content_layer_updater.h

Index: cc/resources/skpicture_content_layer_updater.h
diff --git a/cc/resources/skpicture_content_layer_updater.h b/cc/resources/skpicture_content_layer_updater.h
index 511d8ee9bfd48b93254a9a22741a0b61859345b4..34a492186402a89eebc8182a3aba0745b7557d96 100644
--- a/cc/resources/skpicture_content_layer_updater.h
+++ b/cc/resources/skpicture_content_layer_updater.h
@@ -1,4 +1,4 @@
-// Copyright 2011 The Chromium Authors. All rights reserved.
+// Copyright 2014 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.
 
@@ -14,11 +14,8 @@ namespace cc {
 
 class LayerPainter;
 
-// This class records the content_rect into an SkPicture. Subclasses, provide
-// different implementations of tile updating based on this recorded picture.
-// The BitmapSkPictureContentLayerUpdater and
-// FrameBufferSkPictureContentLayerUpdater are two examples of such
-// implementations.
+// This class records the content_rect into an SkPicture. Subclass provides

[enne (OOO), 2014/01/08 17:51:45]

This looks unrelated to your change description.  Can you stick it in another
patch?

[simonhong, 2014/01/09 04:36:25]

Removed and sent out another cl.

+// SkCanvas to DrawPicture() for tile updating based on this recorded picture.
 class SkPictureContentLayerUpdater : public ContentLayerUpdater {
  protected:
   SkPictureContentLayerUpdater(