Reduce the memory usage of bookmarks storage

components/bookmarks/browser/bookmark_model.cc

 // Copyright 2014 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 "components/bookmarks/browser/bookmark_model.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
@@ skipping 464 matching lines @@
 
   if (!icon_url.is_empty()) {
     // Log Histogram to determine how often |icon_url| is non empty in
     // practice.
     // TODO(pkotwicz): Do something more efficient if |icon_url| is non-empty
     // many times a day for each user.
     UMA_HISTOGRAM_BOOLEAN("Bookmarks.OnFaviconsChangedIconURL", true);
 
     base::AutoLock url_lock(url_lock_);
     for (const BookmarkNode* node : nodes_ordered_by_url_set_) {
-      if (icon_url == node->icon_url())
+      if (node->icon_url() && icon_url == *node->icon_url())
         to_update.insert(node);
     }
   }
 
   for (const BookmarkNode* node : to_update) {
     // Rerequest the favicon.
     BookmarkNode* mutable_node = AsMutable(node);
     mutable_node->InvalidateFavicon();
     CancelPendingFaviconLoadRequests(mutable_node);
     for (BookmarkModelObserver& observer : observers_)
@@ skipping 627 matching lines @@
   undo_delegate_ = undo_delegate;
   if (undo_delegate_)
     undo_delegate_->SetUndoProvider(this);
 }
 
 BookmarkUndoDelegate* BookmarkModel::undo_delegate() const {
   return undo_delegate_ ? undo_delegate_ : empty_undo_delegate_.get();
 }
 
 }  // namespace bookmarks