Convert extension action icons code to use ImageSkia instead of SkBitmap

ui/gfx/image/image_skia_operations.h

Index: ui/gfx/image/image_skia_operations.h
diff --git a/ui/gfx/image/image_skia_operations.h b/ui/gfx/image/image_skia_operations.h
index 042c836432e62ad5351ed415765ed88c078534b3..878e79ad5d4e3aec59f8b7379311cb9bc3e4e633 100644
--- a/ui/gfx/image/image_skia_operations.h
+++ b/ui/gfx/image/image_skia_operations.h
@@ -24,6 +24,11 @@ class UI_EXPORT ImageSkiaOperations {
                                       const ImageSkia& second,
                                       double alpha);
 
+  // Creates new image by painting first and second image respectively.
+  // The second image is centered in respect to the first image.

[Jeffrey Yasskin, 2012/08/09 21:39:04]

I've seen code that wants to control whether centered images round up or down
when they can't be exactly centered. Do you want to expose that here?

[tbarzic, 2012/08/10 06:24:08]

might be a good idea, but I'd leave it outside of scope of this change..

[Jeffrey Yasskin, 2012/08/10 07:40:35]

SGTM.

+  static ImageSkia CreateSuperimposedImage(const ImageSkia& first,
+                                           const ImageSkia& second);
+
   // Create an image that is the original image masked out by the mask defined
   // in the alpha image. The images must use the kARGB_8888_Config config and
   // be of equal dimensions.