Cleanup HistoryService and HistoryBackend interface

components/history/core/browser/history_client.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/history/core/browser/history_client.h"
 
 namespace history {
 
+HistoryClient::HistoryClient() {
+}
+
 void HistoryClient::BlockUntilBookmarksLoaded() {
 }
 
 bool HistoryClient::IsBookmarked(const GURL& url) {
   return false;
 }
 
 void HistoryClient::GetBookmarks(std::vector<URLAndTitle>* bookmarks) {
 }
 
 void HistoryClient::NotifyProfileError(sql::InitStatus init_status) {
 }
 
 bool HistoryClient::ShouldReportDatabaseError() {
   return false;
 }
 
-HistoryClient::HistoryClient() {
-}
-
-}
+}  // namespace history