Sync: Optimize FavIcon callbacks from bookmark model.

chrome/browser/sync/glue/bookmark_change_processor.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/bookmark_change_processor.h"
 
 #include <map>
 #include <stack>
 #include <vector>
 
@@ skipping 391 matching lines @@
     }
   }
 
   UpdateTransactionVersion(new_version, model,
                            std::vector<const BookmarkNode*>(1, child));
 }
 
 void BookmarkChangeProcessor::BookmarkNodeFaviconChanged(
     BookmarkModel* model,
     const BookmarkNode* node) {
+  if (!CanSyncNode(node)) {
+    return;
+  }
+
+  // We shouldn't see changes to the top-level nodes.
+  if (model->is_permanent_node(node)) {
+    NOTREACHED() << "Saw Favicon update to permanent node!";
+    return;
+  }
+
+  // Ignore changes with empty images. This can happen if the favicon is
+  // still being loaded.
+  const gfx::Image& favicon = model->GetFavicon(node);
+  if (favicon.IsEmpty()) {
+    return;
+  }
+
   BookmarkNodeChanged(model, node);
 }
 
 void BookmarkChangeProcessor::BookmarkNodeChildrenReordered(
     BookmarkModel* model, const BookmarkNode* node) {
   if (!CanSyncNode(node))
     return;
   int64 new_version = syncer::syncable::kInvalidTransactionVersion;
   std::vector<const BookmarkNode*> children;
   {
@@ skipping 465 matching lines @@
     updated_specifics.set_icon_url(bookmark_node->icon_url().spec());
     sync_node->SetBookmarkSpecifics(updated_specifics);
   }
 }
 
 bool BookmarkChangeProcessor::CanSyncNode(const BookmarkNode* node) {
   return bookmark_model_->client()->CanSyncNode(node);
 }
 
 }  // namespace browser_sync