[NOT READY FOR REVIEW YET]workers: Some refactoring to allow creating new kind of worker threads

Source/core/workers/WorkerThread.cpp

Index: Source/core/workers/WorkerThread.cpp
diff --git a/Source/core/workers/WorkerThread.cpp b/Source/core/workers/WorkerThread.cpp
index a08d7c5ec5afcd791cf69cdad1a0558aedfa4ffb..2a49ad36eca54674d50632780125bddf77d69efe 100644
--- a/Source/core/workers/WorkerThread.cpp
+++ b/Source/core/workers/WorkerThread.cpp
@@ -248,6 +248,7 @@ WorkerThread::WorkerThread(WorkerLoaderProxy& workerLoaderProxy, WorkerReporting
     , m_startupData(startupData)
     , m_shutdownEvent(adoptPtr(blink::Platform::current()->createWaitableEvent()))
     , m_terminationEvent(adoptPtr(blink::Platform::current()->createWaitableEvent()))
+    , m_isolate(nullptr)
 {
     MutexLocker lock(threadSetMutex());
     workerThreads().add(this);
@@ -265,7 +266,7 @@ void WorkerThread::start()
     if (m_thread)
         return;
 
-    m_thread = WebThreadSupportingGC::create("WebCore: Worker");
+    m_thread = createWebThreadSupportingGC();
     m_thread->postTask(new Task(WTF::bind(&WorkerThread::initialize, this)));
 }
 
@@ -283,6 +284,12 @@ PlatformThreadId WorkerThread::platformThreadId() const
     return m_thread->platformThread().threadId();
 }
 
+v8::Isolate* WorkerThread::isolate() const
+{
+    ASSERT(isCurrentThread());
+    return m_isolate;
+}
+
 void WorkerThread::initialize()
 {
     KURL scriptURL = m_startupData->m_scriptURL;
@@ -303,6 +310,9 @@ void WorkerThread::initialize()
         m_microtaskRunner = adoptPtr(new MicrotaskRunner);
         m_thread->addTaskObserver(m_microtaskRunner.get());
         m_thread->attachGC();
+
+        m_isolate = initializeIsolate();
+
         m_workerGlobalScope = createWorkerGlobalScope(m_startupData.release());
 
         m_sharedTimer = adoptPtr(new WorkerSharedTimer(this));
@@ -329,6 +339,19 @@ void WorkerThread::initialize()
     postDelayedTask(createSameThreadTask(&WorkerThread::idleHandler, this), kShortIdleHandlerDelayMs);
 }
 
+v8::Isolate* WorkerThread::initializeIsolate()
+{
+    ASSERT(isCurrentThread());
+    v8::Isolate* isolate = V8PerIsolateData::initialize();
+    V8Initializer::initializeWorker(isolate);
+    return isolate;
+}
+
+PassOwnPtr<WebThreadSupportingGC> WorkerThread::createWebThreadSupportingGC()
+{
+    return WebThreadSupportingGC::create("WebCore: Worker");
+}
+
 void WorkerThread::cleanup()
 {