Add support for PNG representation in gfx::Image

ui/gfx/image/image_unittest_util.h

 // Copyright (c) 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.
 
 // Because the unit tests for gfx::Image are spread across multiple
 // implementation files, this header contains the reusable components.
 
 #ifndef UI_GFX_IMAGE_IMAGE_UNITTEST_UTIL_H_
 #define UI_GFX_IMAGE_IMAGE_UNITTEST_UTIL_H_
 
@@ skipping 22 matching lines @@
 
 bool IsEqual(const gfx::Image& image1, const gfx::Image& image2);
 
 bool IsEmpty(const gfx::Image& image);
 
 PlatformImage CreatePlatformImage();
 
 gfx::Image::RepresentationType GetPlatformRepresentationType();
 
 PlatformImage ToPlatformType(const gfx::Image& image);
+PlatformImage CopyPlatformType(const gfx::Image& image);
 
 bool IsPlatformImageValid(PlatformImage image);
 
 bool PlatformImagesEqual(PlatformImage image1, PlatformImage image2);
 
 }  // namespace test
 }  // namespace gfx
 
 #endif  // UI_GFX_IMAGE_IMAGE_UNITTEST_UTIL_H_