exhibit 1: explicit null checks

chrome/browser/ui/gtk/hung_renderer_dialog_gtk.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/browser_dialogs.h"
 
 #include <gtk/gtk.h>
 
 #include "base/process_util.h"
 #include "base/utf_string_conversions.h"
@@ skipping 173 matching lines @@
   gtk_list_store_clear(model_);
 
   GtkTreeIter tree_iter;
   for (TabContentsIterator it; !it.done(); ++it) {
     if (it->web_contents()->GetRenderProcessHost() ==
         hung_contents->GetRenderProcessHost()) {
       gtk_list_store_append(model_, &tree_iter);
       std::string title = UTF16ToUTF8(it->web_contents()->GetTitle());
       if (title.empty())
         title = UTF16ToUTF8(CoreTabHelper::GetDefaultTitle());
-      SkBitmap favicon = it->favicon_tab_helper()->GetFavicon().AsBitmap();
+      const gfx::Image& icon = it->favicon_tab_helper()->GetFavicon();
+      SkBitmap favicon = icon.IsEmpty() ? SkBitmap() : *icon.ToSkBitmap();
 
       GdkPixbuf* pixbuf = NULL;
       if (favicon.width() > 0)
         pixbuf = gfx::GdkPixbufFromSkBitmap(favicon);
       gtk_list_store_set(model_, &tree_iter,
           COL_FAVICON, pixbuf,
           COL_TITLE, title.c_str(),
           -1);
       if (pixbuf)
         g_object_unref(pixbuf);
@@ skipping 56 matching lines @@
     g_instance->ShowForWebContents(contents);
   }
 }
 
 void HideHungRendererDialog(WebContents* contents) {
   if (!logging::DialogsAreSuppressed() && g_instance)
     g_instance->EndForWebContents(contents);
 }
 
 }  // namespace chrome