Add Observer in FaviconTabHelper

chrome/browser/favicon/favicon_handler.h

Index: chrome/browser/favicon/favicon_handler.h
diff --git a/chrome/browser/favicon/favicon_handler.h b/chrome/browser/favicon/favicon_handler.h
index 46a507ebd6b9de5f264a824799d43a0cc82e6b19..45d44eb7492885b376cd128343b5ef7380b75575 100644
--- a/chrome/browser/favicon/favicon_handler.h
+++ b/chrome/browser/favicon/favicon_handler.h
@@ -148,10 +148,12 @@ class FaviconHandler {
   // Returns true if the favicon should be saved.
   virtual bool ShouldSaveFavicon(const GURL& url);
 
-  // Notifies the driver that the favicon for the active entry was updated.
-  // |icon_url_changed| is true if a favicon with a different icon URL has been
-  // selected since the previous call to NotifyFaviconUpdated().
-  virtual void NotifyFaviconUpdated(bool icon_url_changed);
+  // Notifies the driver that the icon was updated and could be retreived

[sky, 2014/10/29 15:50:55]

retrieved

+  // from FaviconService, the favicon is also availabe from the active entry
+  // if download_largest_icon_ is not enabled for FAVICON type of icon.
+  // |icon_url| is current icon url and used to check whether a different icon
+  // URL has been selected since the previous call to NotifyFaviconUpdated().
+  virtual void NotifyFaviconUpdated(const GURL& icon_url);
 
  private:
   friend class TestFaviconHandler; // For testing
@@ -295,6 +297,10 @@ class FaviconHandler {
   // the image is for a favicon).
   FaviconCandidate best_favicon_candidate_;
 
+  // The URL of TOUCH_ICON or TOUCH_PRCOMPOSED_ICON which has been used to
+  // notify the driver in the previous call of NotifyFaviconUpdated().
+  GURL notified_touch_icon_url_;
+
   DISALLOW_COPY_AND_ASSIGN(FaviconHandler);
 };