Add Observer in FaviconTabHelper

chrome/browser/favicon/favicon_handler.h

 // Copyright (c) 2012 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_FAVICON_FAVICON_HANDLER_H_
 #define CHROME_BROWSER_FAVICON_FAVICON_HANDLER_H_
 
 #include <deque>
 #include <map>
 #include <vector>
@@ skipping 208 matching lines @@
                               const gfx::Image& image,
                               float score,
                               favicon_base::IconType icon_type);
 
   // Sets the image data for the favicon.
   void SetFavicon(const GURL& url,
                   const GURL& icon_url,
                   const gfx::Image& image,
                   favicon_base::IconType icon_type);
 
   // Sets the favicon's data.

[sky, 2014/10/30 03:34:31]

update comment.

[michaelbai, 2014/10/30 19:22:50]

Done.

-  void SetFaviconOnActivePage(const std::vector<
+  gfx::Image SelectFaviconFrames(const std::vector<
       favicon_base::FaviconRawBitmapResult>& favicon_bitmap_results);
   void SetFaviconOnActivePage(const GURL& icon_url, const gfx::Image& image);
 
   // Return the current candidate if any.
   favicon::FaviconURL* current_candidate() {
     return (!image_urls_.empty()) ? &image_urls_.front() : NULL;
   }
 
   // Returns whether the page's url changed since the favicon was requested.
   bool PageChangedSinceFaviconWasRequested();
@@ skipping 51 matching lines @@
   // Best image we've seen so far.  As images are downloaded from the page they
   // are stored here. When there is an exact match, or no more images are
   // available the favicon service and the current page are updated (assuming
   // the image is for a favicon).
   FaviconCandidate best_favicon_candidate_;
 
   DISALLOW_COPY_AND_ASSIGN(FaviconHandler);
 };
 
 #endif  // CHROME_BROWSER_FAVICON_FAVICON_HANDLER_H_