Add option to force document level passive event listeners as a runtime feature.

third_party/WebKit/Source/core/events/AddEventListenerOptionsDefaults.h

 // 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.
 
 #ifndef AddEventListenerOptionsDefaults_h
 #define AddEventListenerOptionsDefaults_h
 
 namespace blink {
 
 // Defines the default for 'passive' field used in the AddEventListenerOptions interface
 // when javascript calls addEventListener.
 // |False| is the default specified in
 // https://dom.spec.whatwg.org/#dictdef-addeventlisteneroptions. However
 // specifying a different default value is useful in demonstrating the
 // power of passive event listeners.
 enum class PassiveListenerDefault {
     False, // Default of false.
     True, // Default of true.
-    DocumentTrue, // Default of true for document level elements, false otherwise.
     ForceAllTrue // Force all values to be true even when specified.
 };
 
 } // namespace blink
 
 #endif // AddEventListenerOptionsDefaults_h