Revert r21117 as it caused reliability failures....

chrome/worker/worker_thread.cc

Index: chrome/worker/worker_thread.cc
===================================================================
--- chrome/worker/worker_thread.cc	(revision 21215)
+++ chrome/worker/worker_thread.cc	(working copy)
@@ -15,22 +15,37 @@
     base::LINKER_INITIALIZED);
 
 
-WorkerThread::WorkerThread() {
+WorkerThread::WorkerThread()
+    : ChildThread(base::Thread::Options(MessageLoop::TYPE_DEFAULT,
+                                        kV8StackSize)) {
+}
+
+WorkerThread::~WorkerThread() {
+}
+
+WorkerThread* WorkerThread::current() {
+  return lazy_tls.Pointer()->Get();
+}
+
+void WorkerThread::Init() {
   lazy_tls.Pointer()->Set(this);
+  ChildThread::Init();
   webkit_client_.reset(new WorkerWebKitClientImpl);
   WebKit::initialize(webkit_client_.get());
 }
 
-WorkerThread::~WorkerThread() {
+void WorkerThread::CleanUp() {
   // Shutdown in reverse of the initialization order.
-  WebKit::shutdown();
+
+  if (webkit_client_.get()) {
+    WebKit::shutdown();
+    webkit_client_.reset();
+  }
+
+  ChildThread::CleanUp();
   lazy_tls.Pointer()->Set(NULL);
 }
 
-WorkerThread* WorkerThread::current() {
-  return lazy_tls.Pointer()->Get();
-}
-
 void WorkerThread::OnControlMessageReceived(const IPC::Message& msg) {
   IPC_BEGIN_MESSAGE_MAP(WorkerThread, msg)
     IPC_MESSAGE_HANDLER(WorkerProcessMsg_CreateWorker, OnCreateWorker)