Remove ImageLoadingTracker class, as it is not used anymore.

* Remove related methods in Extension: Set/GetCachedImage
* Remove related unit tests
* Update all comments mentioning ImageLoadingTracker to mention ImageLoader instead

BUG=163929
[email protected] (for mechanical changes in chrome/.)

Review URL: https://chromiumcodereview.appspot.com/12213093

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182039 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/tab_helper.h b/chrome/browser/extensions/tab_helper.h
index 3dd1d40..e0cc900 100644
--- a/chrome/browser/extensions/tab_helper.h
+++ b/chrome/browser/extensions/tab_helper.h
@@ -15,7 +15,6 @@
 #include "chrome/browser/extensions/active_tab_permission_granter.h"
 #include "chrome/browser/extensions/app_notify_channel_setup.h"
 #include "chrome/browser/extensions/extension_function_dispatcher.h"
-#include "chrome/browser/extensions/image_loading_tracker.h"
 #include "chrome/common/web_apps.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ -29,6 +28,10 @@
 struct LoadCommittedDetails;
 }
 
+namespace gfx {
+class Image;
+}
+
 namespace extensions {
 class Extension;
 class LocationBarController;
@@ -199,8 +202,8 @@
 
   // App extensions related methods:
 
-  // Resets app_icon_ and if |extension| is non-null creates a new
-  // ImageLoadingTracker to load the extension's image.
+  // Resets app_icon_ and if |extension| is non-null uses ImageLoader to load
+  // the extension's image asynchronously.
   void UpdateExtensionAppIcon(const Extension* extension);
 
   const Extension* GetExtension(const std::string& extension_app_id);