Mountain Lion: use the system download progress.

base/supports_user_data.cc

 // Copyright (c) 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 "base/supports_user_data.h"
 
 namespace base {
 
 SupportsUserData::SupportsUserData() {}
 
 SupportsUserData::Data* SupportsUserData::GetUserData(const void* key) const {
   DataMap::const_iterator found = user_data_.find(key);
   if (found != user_data_.end())
     return found->second.get();
   return NULL;
 }
 
 void SupportsUserData::SetUserData(const void* key, Data* data) {
   user_data_[key] = linked_ptr<Data>(data);
 }
 
+void SupportsUserData::RemoveUserData(const void* key) {
+  user_data_.erase(key);
+}
+
 SupportsUserData::~SupportsUserData() {}
 
 }  // namespace base