Remove unused ThumbnailDatabase::UpdateIconMapping() and ThumbnailDatabase::CloneIconMappings()

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 d122e90668ec421a54ee8680fbbd3bbd2bfbc3b2..e2379671ceda7ae2b10657f7053d1382971116a8 100644
--- a/components/favicon/core/favicon_service.h
+++ b/components/favicon/core/favicon_service.h
@@ -171,13 +171,6 @@ class FaviconService : public KeyedService {
   // Marks all types of favicon for the page as being out of date.
   void SetFaviconOutOfDateForPage(const GURL& page_url);
 
-  // Clones all icons from an existing page. This associates the icons from
-  // |old_page_url| with |new_page_url|, provided |new_page_url| has no
-  // recorded associations to any other icons.
-  // Needed if you want to declare favicons (tentatively) in advance, before a
-  // page is ever visited.
-  void CloneFavicon(const GURL& old_page_url, const GURL& new_page_url);
-
   // Allows the importer to set many favicons for many pages at once. The pages
   // must exist, any favicon sets for unknown pages will be discarded. Existing
   // favicons will not be overwritten.