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 62 matching lines @@
     return false;
   collectHistogramMetrics(*frame);
 
   DCHECK(frame->document());
   DCHECK(frame->page());
 
   if (!frame->page()->isPageVisible())
     return false;
 
   // 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.");
-    }
+  // runtime flag. Please pay attention to the user gesture code below.
+  if (RuntimeEnabledFeatures::featurePolicyEnabled() &&
+      !isFeatureEnabledInFrame(blink::kVibrateFeature, frame)) {
+    frame->domWindow()->printErrorMessage(
+        "Navigator.vibrate() is not enabled in feature policy for this "
+        "frame.");
     return false;
   }
 
+  if (!RuntimeEnabledFeatures::featurePolicyEnabled() &&
+      frame->isCrossOriginSubframe() && !frame->hasReceivedUserGesture()) {
+    frame->domWindow()->printErrorMessage(
+        "Blocked call to navigator.vibrate inside a cross-origin iframe "
+        "because the frame has never been activated by the user: "
+        "https://www.chromestatus.com/feature/5682658461876224.");
+    return false;
+  }
+
   return NavigatorVibration::from(navigator).controller(*frame)->vibrate(
       pattern);
 }
 
 // static
 void NavigatorVibration::collectHistogramMetrics(const LocalFrame& frame) {
   NavigatorVibrationType type;
   bool userGesture = UserGestureIndicator::processingUserGesture();
   UseCounter::count(&frame, UseCounter::NavigatorVibrate);
   if (!frame.isMainFrame()) {
@@ skipping 55 matching lines @@
   }
 }
 
 DEFINE_TRACE(NavigatorVibration) {
   visitor->trace(m_controller);
   Supplement<Navigator>::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink