Work around for a crasher with the select popup on Mac.

chrome/renderer/render_view.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/renderer/render_view.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 5665 matching lines @@
                                    IPC::PlatformFileForTransit file_for_transit,
                                    int message_id) {
   pepper_delegate_.OnAsyncFileOpened(
       error_code,
       IPC::PlatformFileForTransitToPlatformFile(file_for_transit),
       message_id);
 }
 
 #if defined(OS_MACOSX)
 void RenderView::OnSelectPopupMenuItem(int selected_index) {
+  if (external_popup_menu_ == NULL) {
+    // Crash reports from the field indicate that we can be notified with a
+    // NULL external popup menu (we probably get notified twice).
+    // If you hit this please file a bug against jcivelli and include the page
+    // and steps to repro.
+    NOTREACHED();
+    return;
+  }
   external_popup_menu_->DidSelectItem(selected_index);
   external_popup_menu_.reset();
 }
 #endif
 
 void RenderView::AddErrorToRootConsole(const string16& message) {
   if (webview() && webview()->mainFrame()) {
     webview()->mainFrame()->addMessageToConsole(
         WebConsoleMessage(WebConsoleMessage::LevelError, message));
   }
 }