Enabled a number of worker tests on various platforms.

chrome/test/data/workers/worker_common.js

+if (!self.postMessage) {
+  // This is a shared worker - mimic dedicated worker APIs
+  onconnect = function(event) {
+    event.ports[0].onmessage = function(e) {
+      self.onmessage(e);
+    };
+    self.postMessage = function(msg, ports) {
+      event.ports[0].postMessage(msg, ports);
+    };
+  };
+}
 onmessage = function(evt) {
   if (evt.data == "ping")
     postMessage("pong");
   else if (/eval.+/.test(evt.data)) {
     try {
       postMessage(eval(evt.data.substr(5)));
     } catch (ex) {
       postMessage(ex);
     }
   }
 }