Check that BlockedContents::blocked_popup_container is not NULL before using ...

chrome/browser/content_setting_bubble_model.cc

 // Copyright (c) 2010 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/content_setting_bubble_model.h"
 
 #include "app/l10n_util.h"
 #include "base/command_line.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/blocked_popup_container.h"
@@ skipping 300 matching lines @@
 class ContentSettingPopupBubbleModel : public ContentSettingSingleRadioGroup {
  public:
   ContentSettingPopupBubbleModel(TabContents* tab_contents, Profile* profile,
       ContentSettingsType content_type)
       : ContentSettingSingleRadioGroup(tab_contents, profile, content_type) {
     SetPopups();
   }
 
  private:
   void SetPopups() {
+    // check for crbug.com/53176
+    if (!tab_contents()->blocked_popup_container())
+      return;
     BlockedPopupContainer::BlockedContents blocked_contents;
-    DCHECK(tab_contents()->blocked_popup_container());
     tab_contents()->blocked_popup_container()->GetBlockedContents(
         &blocked_contents);
     for (BlockedPopupContainer::BlockedContents::const_iterator
          i(blocked_contents.begin()); i != blocked_contents.end(); ++i) {
       std::string title(UTF16ToUTF8((*i)->GetTitle()));
       // The popup may not have committed a load yet, in which case it won't
       // have a URL or title.
       if (title.empty())
         title = l10n_util::GetStringUTF8(IDS_TAB_LOADING_TITLE);
       PopupItem popup_item;
@@ skipping 134 matching lines @@
   bubble_content_.resource_identifiers.insert(resource_identifier);
 }
 
 void ContentSettingBubbleModel::Observe(NotificationType type,
                                         const NotificationSource& source,
                                         const NotificationDetails& details) {
   DCHECK(type == NotificationType::TAB_CONTENTS_DESTROYED);
   DCHECK(source == Source<TabContents>(tab_contents_));
   tab_contents_ = NULL;
 }