Extend LargeIconService to fetch missing favicons from a Google server

components/favicon/core/favicon_service.h

Index: components/favicon/core/favicon_service.h
diff --git a/components/favicon/core/favicon_service.h b/components/favicon/core/favicon_service.h
index 10a8174747ea6890cb385dae6e1d2b2649ff97c1..d5ea75448ffcfa144c3d0396d4e67359195ed68d 100644
--- a/components/favicon/core/favicon_service.h
+++ b/components/favicon/core/favicon_service.h
@@ -189,6 +189,14 @@ class FaviconService : public KeyedService {
                            favicon_base::IconType icon_type,
                            const gfx::Image& image) = 0;
 
+  // Same as SetFavicons with two differences: a) the favicon will be initially
+  // set as expired; b) it will be a no-op if there is an existing cached
+  // favicon for *any* type for |page_url|.
+  virtual void SetExpiredFaviconsIfNoneKnown(const GURL& page_url,
+                                             const GURL& icon_url,
+                                             favicon_base::IconType icon_type,
+                                             const gfx::Image& image) = 0;
+
   // Avoid repeated requests to download missing favicon.
   virtual void UnableToDownloadFavicon(const GURL& icon_url) = 0;
   virtual bool WasUnableToDownloadFavicon(const GURL& icon_url) const = 0;