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

third_party/WebKit/public/web/WebSettings.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 89 matching lines @@
         Captions,
         // If available, display subtitles track in preferred language, else display captions.
         Subtitles
     };
 
     // Defines the default for 'passive' field used in the AddEventListenerOptions interface
     // when javascript calls addEventListener.
     enum class PassiveEventListenerDefault {
         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.
     };
 
     // Sets value of a setting by its string identifier from Settings.in and
     // string representation of value. An enum's string representation is the
     // string representation of the integer value of the enum.
     virtual void setFromStrings(const WebString& name, const WebString& value) = 0;
 
     virtual bool mainFrameResizesAreOrientationChanges() const = 0;
     virtual bool shrinksViewportContentToFit() const = 0;
@@ skipping 160 matching lines @@
     virtual void setWideViewportQuirkEnabled(bool) = 0;
     virtual void setXSSAuditorEnabled(bool) = 0;
 
 protected:
     ~WebSettings() { }
 };
 
 } // namespace blink
 
 #endif