For Mac, add AppListViewDelegateObserver::OnShutdown

ui/app_list/views/app_list_view.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 "ui/app_list/views/app_list_view.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 264 matching lines @@
 }
 
 void AppListView::Prerender() {
   app_list_main_view_->Prerender();
 }
 
 void AppListView::OnProfilesChanged() {
   app_list_main_view_->search_box_view()->InvalidateMenu();
 }
 
+void AppListView::OnShutdown() {
+  // Nothing to do on views - the widget will soon be closed, which will tear
+  // everything down.
+}
+
 void AppListView::SetProfileByPath(const base::FilePath& profile_path) {
   delegate_->SetProfileByPath(profile_path);
   app_list_main_view_->ModelChanged();
 }
 
 void AppListView::AddObserver(AppListViewObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void AppListView::RemoveObserver(AppListViewObserver* observer) {
@@ skipping 295 matching lines @@
       speech_view_->layer()->SetTransform(speech_transform);
   }
 
   if (will_appear)
     speech_view_->SetVisible(true);
   else
     app_list_main_view_->SetVisible(true);
 }
 
 }  // namespace app_list