navigator.vibrate() crash avoidance when in a detached state.

Source/modules/vibration/NavigatorVibration.cpp

 /*
  *  Copyright (C) 2012 Samsung Electronics
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Library General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 127 matching lines @@
 
 bool NavigatorVibration::vibrate(Navigator& navigator, unsigned time)
 {
     VibrationPattern pattern;
     pattern.append(time);
     return NavigatorVibration::vibrate(navigator, pattern);
 }
 
 bool NavigatorVibration::vibrate(Navigator& navigator, const VibrationPattern& pattern)
 {
+    if (!navigator.frame())
+        return false;
+
     Page* page = navigator.frame()->page();
     if (!page)
         return false;
 
     if (page->visibilityState() != PageVisibilityStateVisible)
         return false;
 
     return NavigatorVibration::from(*page).vibrate(pattern);
 }
 
 NavigatorVibration& NavigatorVibration::from(Page& page)
 {
     NavigatorVibration* navigatorVibration = static_cast<NavigatorVibration*>(WillBeHeapSupplement<Page>::from(page, supplementName()));
     if (!navigatorVibration) {
         navigatorVibration = new NavigatorVibration(page);
         WillBeHeapSupplement<Page>::provideTo(page, supplementName(), adoptPtrWillBeNoop(navigatorVibration));
     }
     return *navigatorVibration;
 }
 
 const char* NavigatorVibration::supplementName()
 {
     return "NavigatorVibration";
 }
 
 } // namespace WebCore