Add knowledge about blocking and passive event listeners.

third_party/WebKit/public/platform/WebEventListenerProperties.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 WebEventListenerProperties_h
 #define WebEventListenerProperties_h
 
 #include "WebCommon.h"
 
 namespace blink {
 
 enum class WebEventListenerClass {
     Touch, // This value includes "pointer" events.
     MouseWheel // This value includes "wheel" and "mousewheel" events.
 };
 
 // Indicates the variety of event listener types for a given WebEventListenerClass.
 enum class WebEventListenerProperties {
     Nothing, // This should be "None"; but None #defined in X11's X.h
-    Passive,
-    Blocking, // This indicates >= 1 blocking listener (and >= 0 passive listeners)
+    Passive, // This indicates soley passive listeners.

[aelias_OOO_until_Jul13, 2016/02/10 20:33:47]

Typo: "solely"

+    Blocking, // This indicates solely blocking listeners.
+    BlockingAndPassive, // This indicates >= 1 blocking listener and >= 1 passive listeners.
 };
 
 } // namespace blink
 
 #endif