Move unique name generation and tracking into //content.

content/renderer/history_entry.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.
 
 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  *     (http://www.torchmobile.com/)
  *
@@ skipping 156 matching lines @@
       root_->CloneAndReplace(new_entry->weak_ptr_factory_.GetWeakPtr(),
                              new_item, clone_children_of_target, target_frame,
                              render_view->GetMainRenderFrame());
   return new_entry;
 }
 
 HistoryEntry::HistoryNode* HistoryEntry::GetHistoryNodeForFrame(
     RenderFrameImpl* frame) {
   if (!frame->GetWebFrame()->parent())
     return root_history_node();
-  return unique_names_to_items_[frame->GetWebFrame()->uniqueName().utf8()];
+  return unique_names_to_items_[frame->unique_name()];
 }
 
 WebHistoryItem HistoryEntry::GetItemForFrame(RenderFrameImpl* frame) {
   if (HistoryNode* history_node = GetHistoryNodeForFrame(frame))
     return history_node->item();
   return WebHistoryItem();
 }
 
 }  // namespace content