Reviewed by Pavel Feldman.

        Support EventTarget interface in fake workers (both for Worker object
        and WorkerContext). Use MessagePort to implement message passing to
        support passing ports in PostMessage.
        https://bugs.webkit.org/show_bug.cgi?id=36763

        * inspector/front-end/InjectedFakeWorker.js:
        (InjectedFakeWorker.Worker.onmessageGetter):
        (InjectedFakeWorker.Worker.onmessageSetter):
        (InjectedFakeWorker.Worker):
        (InjectedFakeWorker.FakeWorker):
        (InjectedFakeWorker.FakeWorker.prototype.postMessage):
        (InjectedFakeWorker.FakeWorker.prototype.terminate):
        (InjectedFakeWorker.FakeWorker.prototype._onWorkerFrameLoaded):
        (InjectedFakeWorker.FakeWorker.prototype._setupWorkerContext.onmessageGetter):
        (InjectedFakeWorker.FakeWorker.prototype._setupWorkerContext.onmessageSetter):
        (InjectedFakeWorker.FakeWorker.prototype._setupWorkerContext):
        (InjectedFakeWorker.FakeWorker.prototype._addEventListener):
        (InjectedFakeWorker.FakeWorker.prototype._removeEventListener):
        (InjectedFakeWorker.FakeWorker.prototype._callbackWrapper):
        (InjectedFakeWorker.FakeWorker.prototype._handleException):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@56780 268f45cc-cd09-0410-ab3c-d52691b4dbfc