Oilpan: move core/workers to oilpan's heap.

Source/core/dom/MessageChannel.cpp

Index: Source/core/dom/MessageChannel.cpp
diff --git a/Source/core/dom/MessageChannel.cpp b/Source/core/dom/MessageChannel.cpp
index 20a493d97c8b9c20be347bbd628258665b35fd45..b6bfbf7d813a627ef76852283737f8cce033592d 100644
--- a/Source/core/dom/MessageChannel.cpp
+++ b/Source/core/dom/MessageChannel.cpp
@@ -33,6 +33,8 @@
 
 namespace WebCore {
 
+DEFINE_GC_INFO(MessageChannel);
+
 static void createChannel(MessagePort* port1, MessagePort* port2)
 {
     // Create proxies for each endpoint.
@@ -60,4 +62,10 @@ MessageChannel::~MessageChannel()
 {
 }
 
+void MessageChannel::trace(Visitor* visitor)
+{
+    visitor->trace(m_port1);
+    visitor->trace(m_port2);
+}
+
 } // namespace WebCore