Don't request missing favicon on every page request.

chrome/browser/favicon/favicon_tab_helper.cc

Index: chrome/browser/favicon/favicon_tab_helper.cc
diff --git a/chrome/browser/favicon/favicon_tab_helper.cc b/chrome/browser/favicon/favicon_tab_helper.cc
index 768e950c9c49e1377436549f26eee8530ec9dd0a..278deadcdd17162e3936bf69734d493b560ff4c0 100644
--- a/chrome/browser/favicon/favicon_tab_helper.cc
+++ b/chrome/browser/favicon/favicon_tab_helper.cc
@@ -135,6 +135,13 @@ NavigationEntry* FaviconTabHelper::GetActiveEntry() {
 }
 
 int FaviconTabHelper::StartDownload(const GURL& url, int image_size) {
+  FaviconService* favicon_service = FaviconServiceFactory::GetForProfile(
+      profile_, Profile::IMPLICIT_ACCESS);
+  if (favicon_service && favicon_service->IsMissingFavicon(url)) {
+    VLOG(1) << "Skip Missing FavIcon: " << url;

[mef, 2013/04/29 21:55:03]

Should I somehow post a call to DidDownloadFavicon from here?

[pauljensen, 2013/04/30 14:38:04]

I have no idea; I am very unfamiliar with the Favicon logic.  I'd recommend
finding a good OWNER.

+    return 0;
+  }
+
   return web_contents()->DownloadImage(
       url,
       true,
@@ -182,6 +189,15 @@ void FaviconTabHelper::DidDownloadFavicon(
     const GURL& image_url,
     int requested_size,
     const std::vector<SkBitmap>& bitmaps) {
+
+  if (bitmaps.size() == 0) {
+    VLOG(1) << "Missing Favicon:" << image_url;
+    FaviconService* favicon_service = FaviconServiceFactory::GetForProfile(
+        profile_, Profile::IMPLICIT_ACCESS);
+    if (favicon_service)
+      favicon_service->AddMissingFavicon(image_url);
+  }
+
   favicon_handler_->OnDidDownloadFavicon(
       id, image_url, requested_size, bitmaps);
   if (touch_icon_handler_.get()) {