Adds the source ImageLoadingTracker to OnImageLoaded. I need this in a

chrome/browser/extensions/image_loading_tracker.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_
 #define CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_
 
 #include "base/ref_counted.h"
 
 class ExtensionResource;
 class SkBitmap;
 
 namespace gfx {
 class Size;
 }
 
 // The views need to load their icons asynchronously but might be deleted before
 // the images have loaded. This class stays alive while the request is in
 // progress (manages its own lifetime) and keeps track of whether the view still
 // cares about the icon loading.
 // Consider abstracting out a FilePathProvider (ExtensionResource) and moving
 // back to chrome/browser/ if other subsystems want to use it.
 class ImageLoadingTracker
-  : public base::RefCountedThreadSafe<ImageLoadingTracker> {
+    : public base::RefCountedThreadSafe<ImageLoadingTracker> {
  public:
   class Observer {
    public:
     // Will be called when the image with the given index has loaded.
     // The |image| is owned by the tracker, so the observer should make a copy
     // if they need to access it after this call.
-    virtual void OnImageLoaded(SkBitmap* image, size_t index) = 0;
+    virtual void OnImageLoaded(ImageLoadingTracker* source,
+                               SkBitmap* image,
+                               size_t index) = 0;
   };
 
   ImageLoadingTracker(Observer* observer, size_t image_count)
-    : observer_(observer), image_count_(image_count), posted_count_(0) {
+      : observer_(observer),
+        image_count_(image_count),
+        posted_count_(0) {
     AddRef();  // We hold on to a reference to ourself to make sure we don't
                // get deleted until we get a response from image loading (see
                // ImageLoadingDone).
   }
 
   // If there are remaining images to be loaded, the observing object should
   // call this method on its destruction, so that the tracker will not attempt
   // to make any more callbacks to it.
   void StopTrackingImageLoad() {
     observer_ = NULL;
@@ skipping 28 matching lines @@
   // itself when it reaches zero.
   size_t image_count_;
 
   // The number of tasks that have been posted so far.
   size_t posted_count_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageLoadingTracker);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_