Oilpan: Ensure that classes with virtual trace methods always have vtables for their left-most base…

Source/modules/websockets/NewWebSocketChannelImpl.cpp

Index: Source/modules/websockets/NewWebSocketChannelImpl.cpp
diff --git a/Source/modules/websockets/NewWebSocketChannelImpl.cpp b/Source/modules/websockets/NewWebSocketChannelImpl.cpp
index a2569b6905bb77b419747e77df461ae3de96e4fc..2f5afef74d25529f999733585eedb216bbf4d960 100644
--- a/Source/modules/websockets/NewWebSocketChannelImpl.cpp
+++ b/Source/modules/websockets/NewWebSocketChannelImpl.cpp
@@ -72,7 +72,7 @@ public:
     virtual void didFinishLoading() OVERRIDE;
     virtual void didFail(FileError::ErrorCode) OVERRIDE;
 
-    void trace(Visitor* visitor)
+    virtual void trace(Visitor* visitor)
     {
         visitor->trace(m_channel);
     }