Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/history/in_memory_history_backend.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/history/in_memory_history_backend.h"
 
 #include <set>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/history/core/browser/in_memory_database.h"
 #include "components/history/core/browser/url_database.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 
 namespace history {
 
 InMemoryHistoryBackend::InMemoryHistoryBackend()
-    : profile_(nullptr), history_service_(nullptr) {
+    : profile_(nullptr),
+      history_service_observer_(this),
+      history_service_(nullptr) {
 }
 
 InMemoryHistoryBackend::~InMemoryHistoryBackend() {
-  if (history_service_)
-    history_service_->RemoveObserver(this);
 }
 
 bool InMemoryHistoryBackend::Init(const base::FilePath& history_filename) {
   db_.reset(new InMemoryDatabase);
   return db_->InitFromDisk(history_filename);
 }
 
 void InMemoryHistoryBackend::AttachToHistoryService(
     Profile* profile,
     HistoryService* history_service) {
   if (!db_) {
     NOTREACHED();
     return;
   }
 
+  profile_ = profile;
+
   DCHECK(history_service);
+  history_service_observer_.Add(history_service);
   history_service_ = history_service;
-  history_service_->AddObserver(this);
-
-  profile_ = profile;
 
   // TODO(evanm): this is currently necessitated by generate_profile, which
   // runs without a browser process. generate_profile should really create
   // a browser process, at which point this check can then be nuked.
   if (!g_browser_process)
     return;
 
   // Register for the notifications we care about.
   // We only want notifications for the associated profile.
   content::Source<Profile> source(profile_);
@@ skipping 88 matching lines @@
 }
 
 void InMemoryHistoryBackend::OnKeywordSearchTermDeleted(
     const KeywordSearchDeletedDetails& details) {
   // For simplicity, this will not remove the corresponding URLRow, but this is
   // okay, as the main database does not do so either.
   db_->DeleteKeywordSearchTermForURL(details.url_row_id);
 }
 
 }  // namespace history