Add support for PNG representation in gfx::Image

ui/gfx/image/image_unittest_util_mac.mm

Index: ui/gfx/image/image_unittest_util_mac.mm
diff --git a/ui/gfx/image/image_unittest_util_mac.mm b/ui/gfx/image/image_unittest_util_mac.mm
new file mode 100644
index 0000000000000000000000000000000000000000..e0c70639530c05b9a12dc9345b37179088288ea0
--- /dev/null
+++ b/ui/gfx/image/image_unittest_util_mac.mm
@@ -0,0 +1,21 @@
+// 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.
+
+#import <AppKit/AppKit.h>
+
+#include "skia/ext/skia_utils_mac.h"
+#include "ui/gfx/image/image_unittest_util.h"
+
+namespace gfx {
+namespace test {
+
+SkColor GetPlatformImageColor(PlatformImage image) {
+  [image lockFocus];
+  NSColor* color = NSReadPixel(NSMakePoint(10, 10));
+  [image unlockFocus];
+  return NSDeviceColorToSkColor(color);
+}
+
+}  // namespace test
+}  // namespace gfx