Implement empty WorkerInternals interface.

third_party/WebKit/Source/core/testing/WorkerInternals.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/testing/WorkerInternals.h"
+
+namespace blink {
+
+// static
+WorkerInternals* WorkerInternals::create(ScriptState* scriptState)
+{
+    return new WorkerInternals(scriptState);
+}
+
+WorkerInternals::~WorkerInternals()
+{
+}
+
+WorkerInternals::WorkerInternals(ScriptState*)
+{
+}
+
+} // namespace blink