Vibration cannot be canceled during pattern vibration.

Source/modules/vibration/NavigatorVibration.h

 /*
  *  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 17 matching lines @@
 namespace WebCore {
 
 class NavigatorVibration : public Supplement<Navigator> {
 public:
     typedef Vector<unsigned> VibrationPattern;
 
     ~NavigatorVibration();
 
     bool vibrate(const VibrationPattern&);
     void cancelVibration();
+
     // FIXME : Hook suspendVibration() and resumeVibration() into the page
     // visibility feature, when the document.hidden attribute is changed.
     void suspendVibration();
     void resumeVibration();
+
     void timerStartFired(Timer<NavigatorVibration>*);
     void timerStopFired(Timer<NavigatorVibration>*);
 
     static bool vibrate(Navigator*, unsigned time);
     static bool vibrate(Navigator*, const VibrationPattern&);
     static NavigatorVibration* from(Navigator*);
 
+    bool isVibrating() { return m_isVibrating; }
+
 private:
     NavigatorVibration();
     static const char* supplementName();
 
     Timer<NavigatorVibration> m_timerStart;
     Timer<NavigatorVibration> m_timerStop;
     bool m_isVibrating;
     VibrationPattern m_pattern;
 };
 
 } // namespace WebCore
 
 #endif // NavigatorVibration_h