Extend HistoryService with support for favicons from Google servers

components/history/core/browser/history_service.h

Index: components/history/core/browser/history_service.h
diff --git a/components/history/core/browser/history_service.h b/components/history/core/browser/history_service.h
index dd6b19aa490f1898e9413cc7fa355269966a4ef5..765fbe777c80097e28744e93c2ebe84a00d156b8 100644
--- a/components/history/core/browser/history_service.h
+++ b/components/history/core/browser/history_service.h
@@ -761,6 +761,20 @@ class HistoryService : public syncer::SyncableService, public KeyedService {
                    const GURL& icon_url,
                    const std::vector<SkBitmap>& bitmaps);
 
+  // Same as SetFavicons with three differences:
+  // 1) It will be a no-op if there is an existing cached favicon for *any* type
+  //    for |page_url|.
+  // 2) If |icon_url| is known to the database, |bitmaps| will be ignored (i.e.
+  //    the icon won't be overwritten) but the mappings from |page_url| to
+  //    |icon_url| will be stored (conditioned to point 1 above).
+  // 3) If |icon_url| is stored, it will be marked as expired.
+  // The callback will receive whether the write actually happened.
+  void SetLastResortFavicons(const GURL& page_url,
+                             favicon_base::IconType icon_type,
+                             const GURL& icon_url,
+                             const std::vector<SkBitmap>& bitmaps,
+                             base::Callback<void(bool)> callback);
+
   // Used by the FaviconService to mark the favicon for the page as being out
   // of date.
   void SetFaviconsOutOfDateForPage(const GURL& page_url);