content: Remove usage of NOTIFICATION_WEB_CONTENTS_DESTROYED from content

content/test/test_web_contents.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 "content/test/test_web_contents.h"
 
 #include <utility>
 
 #include "content/browser/browser_url_handler_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
@@ skipping 152 matching lines @@
 RenderViewHostDelegateView* TestWebContents::GetDelegateView() {
   if (delegate_view_override_)
     return delegate_view_override_;
   return WebContentsImpl::GetDelegateView();
 }
 
 void TestWebContents::SetOpener(TestWebContents* opener) {
   // This is normally only set in the WebContents constructor, which also
   // registers an observer for when the opener gets closed.
   opener_ = opener;
-  registrar_.Add(this, NOTIFICATION_WEB_CONTENTS_DESTROYED,
-                 Source<WebContents>(opener_));
+  AddDestructionObserver(opener_);
 }
 
 void TestWebContents::AddPendingContents(TestWebContents* contents) {
   // This is normally only done in WebContentsImpl::CreateNewWindow.
   pending_contents_[contents->GetRenderViewHost()->GetRoutingID()] = contents;
-  registrar_.Add(this, NOTIFICATION_WEB_CONTENTS_DESTROYED,
-                 Source<WebContents>(contents));
+  AddDestructionObserver(contents);
 }
 
 void TestWebContents::ExpectSetHistoryLengthAndPrune(
     const SiteInstance* site_instance,
     int history_length,
     int32 min_page_id) {
   expect_set_history_length_and_prune_ = true;
   expect_set_history_length_and_prune_site_instance_ =
       static_cast<const SiteInstanceImpl*>(site_instance);
   expect_set_history_length_and_prune_history_length_ = history_length;
@@ skipping 49 matching lines @@
 }
 
 void TestWebContents::ShowCreatedWidget(int route_id,
                                         const gfx::Rect& initial_pos) {
 }
 
 void TestWebContents::ShowCreatedFullscreenWidget(int route_id) {
 }
 
 }  // namespace content