Detach the dependency from host_content_settings_map to extension.

chrome/browser/content_settings/content_settings_mock_provider.cc

 // Copyright (c) 2011 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/content_settings/content_settings_mock_provider.h"
 
 namespace content_settings {
 
 MockProvider::MockProvider()
     : read_only_(false) {}
@@ skipping 25 matching lines @@
                       content_type,
                       resource_identifier,
                       value);
   return true;
 }
 
 void MockProvider::ShutdownOnUIThread() {
   RemoveAllObservers();
 }
 
+std::string MockProvider::GetProviderName() const {
+  return "mock";
+}
+
+SettingSource MockProvider::GetSettingSource() const {
+  return SETTING_SOURCE_NONE;
+}
+
 }  // namespace content_settings