Don't request missing favicon on every page request.

content/renderer/image_loading_helper.cc

 // Copyright (c) 2013 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.
 
 #include "content/renderer/image_loading_helper.h"
 
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "content/common/image_messages.h"
 #include "content/public/common/url_constants.h"
@@ skipping 36 matching lines @@
       result_images.push_back(data_image);
   } else {
     if (DownloadImage(id, image_url, is_favicon, image_size)) {
       // Will complete asynchronously via ImageLoadingHelper::DidDownloadImage
       return;
     }
   }
 
   Send(new ImageHostMsg_DidDownloadImage(routing_id(),
                                          id,
+                                         0,

[sky, 2013/05/03 20:24:54]

Is 0 right here?

[mef, 2013/05/03 21:45:59]

I think it is more correct than 200, as no request was actually issued.

                                          image_url,
                                          image_size,
                                          result_images));
 }
 
 bool ImageLoadingHelper::DownloadImage(int id,
                                        const GURL& image_url,
                                        bool is_favicon,
                                        int image_size) {
   // Make sure webview was not shut down.
@@ skipping 11 matching lines @@
   return true;
 }
 
 void ImageLoadingHelper::DidDownloadImage(
     int requested_size,
     MultiResolutionImageResourceFetcher* fetcher,
     const std::vector<SkBitmap>& images) {
   // Notify requester of image download status.
   Send(new ImageHostMsg_DidDownloadImage(routing_id(),
                                          fetcher->id(),
+                                         fetcher->http_status_code(),
                                          fetcher->image_url(),
                                          requested_size,
                                          images));
 
   // Remove the image fetcher from our pending list. We're in the callback from
   // MultiResolutionImageResourceFetcher, best to delay deletion.
   ImageResourceFetcherList::iterator iter =
       std::find(image_fetchers_.begin(), image_fetchers_.end(), fetcher);
   if (iter != image_fetchers_.end()) {
     image_fetchers_.weak_erase(iter);
@@ skipping 20 matching lines @@
   IPC_BEGIN_MESSAGE_MAP(ImageLoadingHelper, message)
     IPC_MESSAGE_HANDLER(ImageMsg_DownloadImage, OnDownloadImage)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 }
 
 }  // namespace content