Add the ability to unload the HistoryBackend....

chrome/browser/profile.cc

 // Copyright (c) 2006-2008 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/profile.h"
 
 #include "app/theme_provider.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 287 matching lines @@
 
   virtual HistoryService* GetHistoryService(ServiceAccessType sat) {
     if (sat == EXPLICIT_ACCESS) {
       return profile_->GetHistoryService(sat);
     } else {
       NOTREACHED() << "This profile is OffTheRecord";
       return NULL;
     }
   }
 
+  virtual HistoryService* GetHistoryServiceWithoutCreating() {
+    return profile_->GetHistoryServiceWithoutCreating();
+  }
+
   virtual FaviconService* GetFaviconService(ServiceAccessType sat) {
     if (sat == EXPLICIT_ACCESS) {
       return profile_->GetFaviconService(sat);
     } else {
       NOTREACHED() << "This profile is OffTheRecord";
       return NULL;
     }
   }
 
   virtual WebDataService* GetWebDataService(ServiceAccessType sat) {
@@ skipping 691 matching lines @@
     history_service_.swap(history);
 
     // Send out the notification that the history service was created.
     NotificationService::current()->
         Notify(NotificationType::HISTORY_CREATED, Source<Profile>(this),
                Details<HistoryService>(history_service_.get()));
   }
   return history_service_.get();
 }
 
+HistoryService* ProfileImpl::GetHistoryServiceWithoutCreating() {
+  return history_service_.get();
+}
+
 TemplateURLModel* ProfileImpl::GetTemplateURLModel() {
   if (!template_url_model_.get())
     template_url_model_.reset(new TemplateURLModel(this));
   return template_url_model_.get();
 }
 
 TemplateURLFetcher* ProfileImpl::GetTemplateURLFetcher() {
   if (!template_url_fetcher_.get())
     template_url_fetcher_.reset(new TemplateURLFetcher(this));
   return template_url_fetcher_.get();
@@ skipping 343 matching lines @@
 #endif
   return NULL;
 }
 
 void ProfileImpl::InitSyncService() {
 #ifdef CHROME_PERSONALIZATION
   sync_service_.reset(new ProfileSyncService(this));
   sync_service_->Initialize();
 #endif
 }