Detach the dependency from host_content_settings_map to extension.

chrome/browser/content_settings/content_settings_custom_extension_provider.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 "chrome/browser/content_settings/content_settings_custom_extension_provider.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
 #include "chrome/browser/extensions/api/content_settings/content_settings_store.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
@@ skipping 26 matching lines @@
     const ResourceIdentifier& resource_identifier,
     base::Value* value) {
   return false;
 }
 
 void CustomExtensionProvider::ShutdownOnUIThread() {
   RemoveAllObservers();
   extensions_settings_->RemoveObserver(this);
 }
 
+std::string CustomExtensionProvider::GetProviderName() const {
+  return "extension";
+}
+
+SettingSource CustomExtensionProvider::GetSettingSource() const {
+  return SETTING_SOURCE_EXTENSION;
+}
+
 void CustomExtensionProvider::OnContentSettingChanged(
     const std::string& extension_id,
     bool incognito) {
   if (incognito_ != incognito)
     return;
   // TODO(markusheintz): Be more concise.
   NotifyObservers(ContentSettingsPattern(),
                   ContentSettingsPattern(),
                   CONTENT_SETTINGS_TYPE_DEFAULT,
                   std::string());
 }
 
 }  // namespace content_settings