Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/predictors/autocomplete_action_predictor.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/predictors/autocomplete_action_predictor.h"
 
 #include <math.h>
 
 #include <vector>
 
@@ skipping 51 matching lines @@
 }  // namespace
 
 namespace predictors {
 
 const int AutocompleteActionPredictor::kMaximumDaysToKeepEntry = 14;
 
 AutocompleteActionPredictor::AutocompleteActionPredictor(Profile* profile)
     : profile_(profile),
       main_profile_predictor_(NULL),
       incognito_predictor_(NULL),
-      initialized_(false) {
+      initialized_(false),
+      history_service_observer_(this) {
   if (profile_->IsOffTheRecord()) {
     main_profile_predictor_ = AutocompleteActionPredictorFactory::GetForProfile(
         profile_->GetOriginalProfile());
     DCHECK(main_profile_predictor_);
     main_profile_predictor_->incognito_predictor_ = this;
     if (main_profile_predictor_->initialized_)
       CopyFromMainProfile();
   } else {
     // Request the in-memory database from the history to force it to load so
     // it's available as soon as possible.
@@ skipping 167 matching lines @@
 
     case chrome::NOTIFICATION_OMNIBOX_OPENED_URL: {
       DCHECK(initialized_);
 
       // TODO(dominich): This doesn't need to be synchronous. Investigate
       // posting it as a task to be run later.
       OnOmniboxOpenedUrl(*content::Details<OmniboxLog>(details).ptr());
       break;
     }
 
-    case chrome::NOTIFICATION_HISTORY_LOADED: {
-      TryDeleteOldEntries(content::Details<HistoryService>(details).ptr());
-
-      notification_registrar_.Remove(this,
-                                     chrome::NOTIFICATION_HISTORY_LOADED,
-                                     content::Source<Profile>(profile_));
-      break;
-    }
-
     default:
       NOTREACHED() << "Unexpected notification observed.";
       break;
   }
 }
 
 void AutocompleteActionPredictor::CreateLocalCachesFromDatabase() {
   // Create local caches using the database as loaded. We will garbage collect
   // rows from the caches and the database once the history service is
   // available.
@@ skipping 189 matching lines @@
   DCHECK(db_id_cache_.empty());
 
   for (std::vector<AutocompleteActionPredictorTable::Row>::const_iterator it =
        rows->begin(); it != rows->end(); ++it) {
     const DBCacheKey key = { it->user_text, it->url };
     const DBCacheValue value = { it->number_of_hits, it->number_of_misses };
     db_cache_[key] = value;
     db_id_cache_[key] = it->id;
   }
 
-  // If the history service is ready, delete any old or invalid entries.

[sdefresne, 2014/10/30 17:37:04]

Please restore comment.

[nshaik, 2014/10/30 21:48:35]

Done.

   HistoryService* history_service =
       HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
-  if (!TryDeleteOldEntries(history_service)) {
-    // Wait for the notification that the history service is ready and the URL
-    // DB is loaded.
-    notification_registrar_.Add(this, chrome::NOTIFICATION_HISTORY_LOADED,
-                                content::Source<Profile>(profile_));
-  }
+  TryDeleteOldEntries(history_service);

[sdefresne, 2014/10/30 17:37:03]

Could you keep the old structure and comment and just change how the listening
for the event is done? I.e. write it like that:

if (!TryDeleteOldEntries(history_service)) {
  // ...
  if (history_service)
    history_service_observer_.Add(history_service);
}

[nshaik, 2014/10/30 21:48:35]

Done.

 }
 
 bool AutocompleteActionPredictor::TryDeleteOldEntries(HistoryService* service) {
   CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!profile_->IsOffTheRecord());
   DCHECK(!initialized_);
 
   if (!service)
     return false;
 
   history::URLDatabase* url_db = service->InMemoryDatabase();
-  if (!url_db)
+  if (!url_db) {
+    history_service_observer_.Add(service);

[sdefresne, 2014/10/30 17:37:03]

See previous comment.

[nshaik, 2014/10/30 21:48:35]

Done.

     return false;
+  }
 
   DeleteOldEntries(url_db);
   return true;
 }
 
 void AutocompleteActionPredictor::DeleteOldEntries(
     history::URLDatabase* url_db) {
   CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!profile_->IsOffTheRecord());
   DCHECK(!initialized_);
@@ skipping 92 matching lines @@
   const double number_of_hits = static_cast<double>(value.number_of_hits);
   return number_of_hits / (number_of_hits + value.number_of_misses);
 }
 
 AutocompleteActionPredictor::TransitionalMatch::TransitionalMatch() {
 }
 
 AutocompleteActionPredictor::TransitionalMatch::~TransitionalMatch() {
 }
 
+void AutocompleteActionPredictor::Shutdown() {
+  history_service_observer_.RemoveAll();
+}
+
+void AutocompleteActionPredictor::OnHistoryServiceLoaded(
+    HistoryService* history_service) {
+  TryDeleteOldEntries(history_service);
+  history_service_observer_.Remove(history_service);
+}
+
 }  // namespace predictors