Fix unitialized memory access in workers.

chrome/browser/worker_host/message_port_dispatcher.h

Index: chrome/browser/worker_host/message_port_dispatcher.h
diff --git a/chrome/browser/worker_host/message_port_dispatcher.h b/chrome/browser/worker_host/message_port_dispatcher.h
index 21be0c6142a34e5be2971465e544f9c854e99c4b..16f4d22f1aff4e4fd8089a0a4a4384ce65d1978d 100644
--- a/chrome/browser/worker_host/message_port_dispatcher.h
+++ b/chrome/browser/worker_host/message_port_dispatcher.h
@@ -67,6 +67,16 @@ class MessagePortDispatcher : public NotificationObserver {
                const NotificationSource& source,
                const NotificationDetails& details);
 
+  // Handles the details of removing a message port id. Before calling this,
+  // verify that the message port id exists.
+  void Erase(int message_port_id);
+
+#ifdef NDEBUG
+  bool CheckMessagePortMap(bool check_entanglements) { }
+#else
+  bool CheckMessagePortMap(bool check_entanglements);
+#endif
+
   struct MessagePort {
     // sender and route_id are what we need to send messages to the port.
     IPC::Message::Sender* sender;