Enable hidpi favicons for favicons history does not know about

chrome/browser/sync/glue/bookmark_change_processor.cc

Index: chrome/browser/sync/glue/bookmark_change_processor.cc
diff --git a/chrome/browser/sync/glue/bookmark_change_processor.cc b/chrome/browser/sync/glue/bookmark_change_processor.cc
index cca79d0e78f6518392be7366d87205b8a98030a8..50efea3b23a615bf4aad2ad52207866714a3c51f 100644
--- a/chrome/browser/sync/glue/bookmark_change_processor.cc
+++ b/chrome/browser/sync/glue/bookmark_change_processor.cc
@@ -25,6 +25,7 @@
 #include "sync/internal_api/public/write_node.h"
 #include "sync/internal_api/public/write_transaction.h"
 #include "sync/syncable/entry.h"  // TODO(tim): Investigating bug 121587.
+#include "ui/gfx/favicon_size.h"
 #include "ui/gfx/image/image_util.h"
 
 using content::BrowserThread;
@@ -635,6 +636,11 @@ void BookmarkChangeProcessor::ApplyBookmarkFavicon(
   // which does not collide with others.
   GURL fake_icon_url = bookmark_node->url();
 
+  // As the favicon which is pushed to the sync service from BookmarkModel is
+  // gfx::kFaviconSize in width and height, use gfx::kFaviconSize as a guess of
+  // the size of the bitmap which is recieved from sync.
+  gfx::Size pixel_size(gfx::kFaviconSize, gfx::kFaviconSize);
+
   HistoryService* history =
       HistoryServiceFactory::GetForProfile(profile, Profile::EXPLICIT_ACCESS);
   FaviconService* favicon_service =
@@ -642,10 +648,15 @@ void BookmarkChangeProcessor::ApplyBookmarkFavicon(
 
   history->AddPageNoVisitForBookmark(bookmark_node->url(),
                                      bookmark_node->GetTitle());
-  favicon_service->SetFavicon(bookmark_node->url(),
-                              fake_icon_url,
-                              icon_bytes_vector,
-                              history::FAVICON);
+// The client may have cached the favicon at 2x. Use MergeFavicon() as not to
+// overwrite the cached 2x favicon bitmap.
+scoped_refptr<base::RefCountedMemory> bitmap_data(
+      new base::RefCountedBytes(icon_bytes_vector));
+favicon_service->MergeFavicon(bookmark_node->url(),
+                                fake_icon_url,
+                                history::FAVICON,
+                                bitmap_data,
+                                pixel_size);
 }
 
 // static