Don't request missing favicon on every page request.

chrome/browser/favicon/favicon_tab_helper.h

Index: chrome/browser/favicon/favicon_tab_helper.h
diff --git a/chrome/browser/favicon/favicon_tab_helper.h b/chrome/browser/favicon/favicon_tab_helper.h
index de41009dcbcc55d45d242da9d9d9a7307d33aef2..b0f17a2d8a036c8aeac02b824629fc0754ccd94b 100644
--- a/chrome/browser/favicon/favicon_tab_helper.h
+++ b/chrome/browser/favicon/favicon_tab_helper.h
@@ -72,6 +72,14 @@ class FaviconTabHelper : public content::WebContentsObserver,
   virtual int StartDownload(const GURL& url, int image_size) OVERRIDE;
   virtual void NotifyFaviconUpdated(bool icon_url_changed) OVERRIDE;
 
+  // Favicon download callback.
+  void DidDownloadFavicon(

[mef, 2013/05/08 20:20:01]

I've made it public so I could access it from unit test. I'm not very happy
about this and would love suggestions on avoiding this.

+      int id,
+      int http_status_code,
+      const GURL& image_url,
+      int requested_size,
+      const std::vector<SkBitmap>& bitmaps);
+
  private:
   explicit FaviconTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<FaviconTabHelper>;
@@ -84,13 +92,6 @@ class FaviconTabHelper : public content::WebContentsObserver,
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
 
-  // Favicon download callback.
-  void DidDownloadFavicon(
-      int id,
-      const GURL& image_url,
-      int requested_size,
-      const std::vector<SkBitmap>& bitmaps);
-
   Profile* profile_;
   bool should_fetch_icons_;