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.
+  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.