Bug 1221852 - SharedWorker.port should be always not null, r=smaug

dom/workers/SharedWorker.cpp

@@ -136,7 +136,6 @@ SharedWorker::Close()
 
   if (mMessagePort) {
     mMessagePort->Close();
-    mMessagePort = nullptr;
   }
 }
 

dom/workers/test/sharedWorker_ports.js

@@ -17,6 +17,7 @@ onconnect = function(evt) {
                           test: (evtFromPort2.data.type == "connected"),
                           msg: "The original message received" });
         port.postMessage({type: "finish"});
+        close();
       }
     }
   }

dom/workers/test/test_sharedWorker_ports.html

@@ -28,6 +28,9 @@ sw1.port.onmessage = function(event) {
   }
 
   if (event.data.type == "finish") {
+    info("Finished!");
+    ok(sw1.port, "The port still exists");
+    sw1.port.foo = sw1; // Just a test to see if we leak.
     SimpleTest.finish();
   }
 }