Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/search_engines/chrome_template_url_service_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 "chrome/browser/search_engines/chrome_template_url_service_client.h"
 
 #include "chrome/browser/history/history_service.h"
 #include "components/search_engines/template_url_service.h"
 #include "extensions/common/constants.h"
 
 ChromeTemplateURLServiceClient::ChromeTemplateURLServiceClient(
     HistoryService* history_service)
-    : owner_(NULL), history_service_(history_service) {
+    : owner_(NULL),
+      history_service_observer_(this),
+      history_service_(history_service) {
   // TODO(sky): bug 1166191. The keywords should be moved into the history
   // db, which will mean we no longer need this notification and the history
   // backend can handle automatically adding the search terms as the user
   // navigates.
   if (history_service_)
-    history_service_->AddObserver(this);
+    history_service_observer_.Add(history_service_);
 }
 
 ChromeTemplateURLServiceClient::~ChromeTemplateURLServiceClient() {
 }
 
 void ChromeTemplateURLServiceClient::Shutdown() {
   // ChromeTemplateURLServiceClient is owned by TemplateURLService which is a
   // KeyedService with a dependency on HistoryService, thus |history_service_|
   // outlives the ChromeTemplateURLServiceClient.
   //
   // Remove self from |history_service_| observers in the shutdown phase of the
   // two-phases since KeyedService are not supposed to use a dependend service
   // after the Shutdown call.
-  if (history_service_)
-    history_service_->RemoveObserver(this);
+  history_service_observer_.RemoveAll();
 }
 
 void ChromeTemplateURLServiceClient::SetOwner(TemplateURLService* owner) {
   DCHECK(!owner_);
   owner_ = owner;
 }
 
 void ChromeTemplateURLServiceClient::DeleteAllSearchTermsForKeyword(
     TemplateURLID id) {
   if (history_service_)
@@ skipping 37 matching lines @@
   DCHECK_EQ(history_service_, history_service);
   if (!owner_)
     return;
 
   TemplateURLService::URLVisitedDetails visited_details;
   visited_details.url = row.url();
   visited_details.is_keyword_transition =
       ui::PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_KEYWORD);
   owner_->OnHistoryURLVisited(visited_details);
 }