Allow vibrate in cross-origin iframes with user gesture.

third_party/WebKit/Source/bindings/core/v8/ConditionalFeatures.cpp

 // Copyright 2016 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 "bindings/core/v8/ConditionalFeatures.h"
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8Document.h"
 #include "bindings/core/v8/V8HTMLLinkElement.h"
 #include "bindings/core/v8/V8Navigator.h"
@@ skipping 75 matching lines @@
                                           scriptState, v8::Local<v8::Object>(),
                                           v8::Local<v8::Function>());
 }
 
 bool isFeatureEnabledInFrame(const FeaturePolicy::Feature& feature,
                              const LocalFrame* frame) {
   // If there is no frame, or if feature policy is disabled, use defaults.
   bool enabledByDefault =
       (feature.defaultPolicy == FeaturePolicy::FeatureDefault::EnableForAll ||
        (feature.defaultPolicy == FeaturePolicy::FeatureDefault::EnableForSelf &&
-        !frame->isCrossOriginSubframe()));
+        (!frame->isCrossOriginSubframe() || frame->hasReceivedUserGesture())));

[ojan, 2017/01/22 23:02:54]

I don't think you want this here. This is the generic FeaturePolicy
implementation, which will eventually be exposed to web authors. This check
should go in NavigatorVibration.cpp for now. If we find it's more general, we
might want a helper function later.

   if (!RuntimeEnabledFeatures::featurePolicyEnabled() || !frame)
     return enabledByDefault;
   FeaturePolicy* featurePolicy = frame->securityContext()->getFeaturePolicy();
   // The policy should always be initialized before checking it to ensure we
   // properly inherit the parent policy.
   DCHECK(featurePolicy);
 
   // Otherwise, check policy.
   return featurePolicy->isFeatureEnabled(feature);
 }
 
 }  // namespace blink