Allow vibrate in cross-origin iframes with user gesture.

third_party/WebKit/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 70 matching lines @@
 
   // TODO(lunalu): When FeaturePolicy is ready, take out the check for the
   // runtime flag.
   if (!isFeatureEnabledInFrame(blink::kVibrateFeature, frame)) {
     if (RuntimeEnabledFeatures::featurePolicyEnabled()) {
       frame->domWindow()->printErrorMessage(
           "Navigator.vibrate() is not enabled in feature policy for this "
           "frame.");
     } else {
       frame->domWindow()->printErrorMessage(
-          "A call of navigator.vibrate will be no-op inside cross-origin "
-          "iframes: https://www.chromestatus.com/feature/5682658461876224.");
+          "A call of navigator.vibrate will be no-op inside a cross-origin "
+          "iframe if there is no user activation on the iframe: "
+          "https://www.chromestatus.com/feature/5682658461876224.");
     }
     return false;
   }
 
   return NavigatorVibration::from(navigator).controller(*frame)->vibrate(
       pattern);
 }
 
 // static
 void NavigatorVibration::collectHistogramMetrics(const LocalFrame& frame) {
@@ skipping 59 matching lines @@
   }
 }
 
 DEFINE_TRACE(NavigatorVibration) {
   visitor->trace(m_controller);
   Supplement<Navigator>::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink