Add support for multiple icon sizes for Mac platform apps

This is the combined version of the following CLs:
http://codereview.chromium.org/9428025/
http://codereview.chromium.org/9500007/
http://codereview.chromium.org/9535002/

BUG=112651
TEST=

Review URL: https://chromiumcodereview.appspot.com/9586018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124875 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_tab_helper.h b/chrome/browser/extensions/extension_tab_helper.h
index ef1bd99c..dd1edc8a0 100644
--- a/chrome/browser/extensions/extension_tab_helper.h
+++ b/chrome/browser/extensions/extension_tab_helper.h
@@ -122,7 +122,8 @@
   void UpdateExtensionAppIcon(const Extension* extension);
 
   // ImageLoadingTracker::Observer.
-  virtual void OnImageLoaded(SkBitmap* image, const ExtensionResource& resource,
+  virtual void OnImageLoaded(const gfx::Image& image,
+                             const std::string& extension_id,
                              int index) OVERRIDE;
 
   // WebstoreInlineInstaller::Delegate.