[DevTools] Always send a copy of worker message through the page.

third_party/WebKit/LayoutTests/inspector-protocol/resources/worker-console-worker.js

 self.onmessage = function(event)
 {
-    console.log(event.data);
+    if (event.data.indexOf("throw") === 0)
+        Promise.reject(event.data);
+    else
+        console.log(event.data);
     self.postMessage(event.data);
 }
 self.postMessage("ready");