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

Source/core/workers/AbstractWorker.h

Index: Source/core/workers/AbstractWorker.h
diff --git a/Source/core/workers/AbstractWorker.h b/Source/core/workers/AbstractWorker.h
index 30bf6cd228fc84d52f9e45ebfba5f90c671b434a..66e361dee364581e90f518913ecd682e5c0f421f 100644
--- a/Source/core/workers/AbstractWorker.h
+++ b/Source/core/workers/AbstractWorker.h
@@ -58,6 +58,8 @@ public:
     AbstractWorker(ExecutionContext*);
     virtual ~AbstractWorker();
 
+    virtual void trace(Visitor* visitor) { EventTargetWithInlineData::trace(visitor); }
+
 protected:
     // Helper function that converts a URL to an absolute URL and checks the result for validity.
     KURL resolveURL(const String& url, ExceptionState&);