Update unit tests after SkFlattenable::getFactory const-ification.

cc/test/skia_common.h

 // Copyright 2012 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_TEST_SKIA_COMMON_H_
 #define CC_TEST_SKIA_COMMON_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "skia/ext/lazy_pixel_ref.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkFlattenable.h"
 
 namespace gfx {
 class Rect;
 class Size;
 }
 
 namespace cc {
 class Picture;
 
 class TestPixelRef : public SkPixelRef {
  public:
   TestPixelRef(int width, int height);
   virtual ~TestPixelRef();
 
-  virtual SkFlattenable::Factory getFactory() OVERRIDE;
+  virtual SkFlattenable::Factory getFactory() const OVERRIDE;
   virtual void* onLockPixels(SkColorTable** color_table) OVERRIDE;
   virtual void onUnlockPixels() OVERRIDE {}
   virtual SkPixelRef* deepCopy(
       SkBitmap::Config config,
       const SkIRect* subset) OVERRIDE;
  private:
   scoped_ptr<char[]> pixels_;
 };
 
 class TestLazyPixelRef : public skia::LazyPixelRef {
  public:
   TestLazyPixelRef(int width, int height);
   virtual ~TestLazyPixelRef();
 
-  virtual SkFlattenable::Factory getFactory() OVERRIDE;
+  virtual SkFlattenable::Factory getFactory() const OVERRIDE;
   virtual void* onLockPixels(SkColorTable** color_table) OVERRIDE;
   virtual void onUnlockPixels() OVERRIDE {}
   virtual bool PrepareToDecode(const PrepareParams& params) OVERRIDE;
   virtual bool MaybeDecoded() OVERRIDE;
   virtual SkPixelRef* deepCopy(
       SkBitmap::Config config,
       const SkIRect* subset) OVERRIDE;
   virtual void Decode() OVERRIDE {}
  private:
   scoped_ptr<char[]> pixels_;
 };
 
 void DrawPicture(unsigned char* buffer,
                  gfx::Rect layer_rect,
                  scoped_refptr<Picture> picture);
 
 void CreateBitmap(gfx::Size size, const char* uri, SkBitmap* bitmap);
 
 }  // namespace cc
 
 #endif  // CC_TEST_SKIA_COMMON_H_