Support "once" event listener option

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

Index: third_party/WebKit/Source/core/events/RegisteredEventListener.h
diff --git a/third_party/WebKit/Source/core/events/RegisteredEventListener.h b/third_party/WebKit/Source/core/events/RegisteredEventListener.h
index b2ff7d2d33aa91e2de8f90f9ba844dd1bd18d9ed..14c9d10155f0d21770cedce518461707b1899dfa 100644
--- a/third_party/WebKit/Source/core/events/RegisteredEventListener.h
+++ b/third_party/WebKit/Source/core/events/RegisteredEventListener.h
@@ -36,8 +36,10 @@ public:
     RegisteredEventListener()
         : m_useCapture(false)
         , m_passive(false)
+        , m_once(false)
         , m_blockedEventWarningEmitted(false)
         , m_passiveForcedForDocumentTarget(false)
+        , m_onceBeingRemoved(false)
     {
     }
 
@@ -45,8 +47,10 @@ public:
         : m_listener(listener)
         , m_useCapture(options.capture())
         , m_passive(options.passive())
+        , m_once(options.once())
         , m_blockedEventWarningEmitted(false)
         , m_passiveForcedForDocumentTarget(options.passiveForcedForDocumentTarget())
+        , m_onceBeingRemoved(false)
     {
     }
 
@@ -61,6 +65,7 @@ public:
         result.setCapture(m_useCapture);
         result.setPassive(m_passive);
         result.setPassiveForcedForDocumentTarget(m_passiveForcedForDocumentTarget);
+        result.setOnce(m_once);
         return result;
     }
 
@@ -79,6 +84,11 @@ public:
         return m_passive;
     }
 
+    bool once() const
+    {
+        return m_once;
+    }
+
     bool capture() const
     {
         return m_useCapture;
@@ -94,6 +104,16 @@ public:
         return m_passiveForcedForDocumentTarget;
     }
 
+    bool onceBeingRemoved() const
+    {
+        return m_onceBeingRemoved;
+    }
+
+    void setOnceBeingRemoved()
+    {
+        m_onceBeingRemoved = true;
+    }
+
     void setBlockedEventWarningEmitted()
     {
         m_blockedEventWarningEmitted = true;
@@ -119,8 +139,10 @@ private:
     Member<EventListener> m_listener;
     unsigned m_useCapture : 1;
     unsigned m_passive : 1;
+    unsigned m_once : 1;
     unsigned m_blockedEventWarningEmitted : 1;
     unsigned m_passiveForcedForDocumentTarget : 1;
+    unsigned m_onceBeingRemoved : 1;
 };
 
 } // namespace blink