exhibit 1: explicit null checks

chrome/browser/ui/content_settings/content_setting_bubble_model.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/ui/content_settings/content_setting_bubble_model.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
@@ skipping 451 matching lines @@
   for (std::vector<TabContents*>::const_iterator
        i = blocked_contents.begin(); i != blocked_contents.end(); ++i) {
     std::string title(UTF16ToUTF8((*i)->web_contents()->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;
     popup_item.title = title;
     // TODO: Make this use gfx::Image.
-    popup_item.bitmap = (*i)->favicon_tab_helper()->GetFavicon().AsBitmap();
+    const gfx::Image& icon = (*i)->favicon_tab_helper()->GetFavicon();
+    popup_item.bitmap = icon.IsEmpty() ? SkBitmap() : *icon.ToSkBitmap();
     popup_item.tab_contents = (*i);
     add_popup(popup_item);
   }
 }
 
 void ContentSettingPopupBubbleModel::OnPopupClicked(int index) {
   if (tab_contents()) {
     tab_contents()->blocked_content_tab_helper()->
         LaunchForContents(bubble_content().popup_items[index].tab_contents);
   }
@@ skipping 331 matching lines @@
     const content::NotificationDetails& details) {
   if (type == chrome::NOTIFICATION_TAB_CONTENTS_DESTROYED) {
     DCHECK_EQ(tab_contents_, content::Source<TabContents>(source).ptr());
     tab_contents_ = NULL;
   } else {
     DCHECK_EQ(chrome::NOTIFICATION_PROFILE_DESTROYED, type);
     DCHECK_EQ(profile_, content::Source<Profile>(source).ptr());
     profile_ = NULL;
   }
 }