Clear EmbeddedWorkerContextClient's thread-local ptr in willDestroyWorkerContext()

content/renderer/service_worker/embedded_worker_context_client.cc

 // Copyright 2013 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 "content/renderer/service_worker/embedded_worker_context_client.h"
 
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/pickle.h"
 #include "base/threading/thread_local.h"
@@ skipping 79 matching lines @@
       service_worker_version_id_(service_worker_version_id),
       service_worker_scope_(service_worker_scope),
       script_url_(script_url),
       worker_devtools_agent_route_id_(worker_devtools_agent_route_id),
       sender_(ChildThread::current()->thread_safe_sender()),
       main_thread_proxy_(base::MessageLoopProxy::current()),
       weak_factory_(this) {
 }
 
 EmbeddedWorkerContextClient::~EmbeddedWorkerContextClient() {
-  // g_worker_client_tls.Pointer()->Get() could be NULL if this gets
-  // deleted before workerContextStarted() is called.
-  g_worker_client_tls.Pointer()->Set(NULL);
 }
 
 bool EmbeddedWorkerContextClient::OnMessageReceived(
     const IPC::Message& msg) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(EmbeddedWorkerContextClient, msg)
     IPC_MESSAGE_HANDLER(EmbeddedWorkerContextMsg_MessageToWorker,
                         OnMessageToWorker)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
@@ skipping 25 matching lines @@
 }
 
 void EmbeddedWorkerContextClient::workerContextStarted(
     blink::WebServiceWorkerContextProxy* proxy) {
   DCHECK(!worker_task_runner_);
   worker_task_runner_ = new WorkerThreadTaskRunner(
       WorkerTaskRunner::Instance()->CurrentWorkerId());
   DCHECK_NE(0, WorkerTaskRunner::Instance()->CurrentWorkerId());
   DCHECK(g_worker_client_tls.Pointer()->Get() == NULL);
   DCHECK(!script_context_);
+  // g_worker_client_tls.Pointer()->Get() could return NULL if this context

[michaeln, 2014/05/22 19:23:52]

this comment seems out of place here, two lines up we assert its null?

[kinuko, 2014/05/23 02:47:48]

Done.

+  // gets deleted before workerContextStarted() is called.
   g_worker_client_tls.Pointer()->Set(this);
   script_context_.reset(new ServiceWorkerScriptContext(this, proxy));
 
   Send(new EmbeddedWorkerHostMsg_WorkerScriptLoaded(embedded_worker_id_));
 
   // Schedule a task to send back WorkerStarted asynchronously,
   // so that at the time we send it we can be sure that the worker
   // script has been evaluated and worker run loop has been started.
   worker_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&EmbeddedWorkerContextClient::SendWorkerStarted,
                  weak_factory_.GetWeakPtr()));
 }
 
 void EmbeddedWorkerContextClient::willDestroyWorkerContext() {
   // At this point OnWorkerRunLoopStopped is already called, so
   // worker_task_runner_->RunsTasksOnCurrentThread() returns false
   // (while we're still on the worker thread).
   script_context_.reset();
+
+  // This also lets the message filter stop dispatching messages to
+  // this client.
+  g_worker_client_tls.Pointer()->Set(NULL);
 }
 
 void EmbeddedWorkerContextClient::workerContextDestroyed() {
+  DCHECK(g_worker_client_tls.Pointer()->Get() == NULL);
+
   // Now we should be able to free the WebEmbeddedWorker container on the
   // main thread.
   main_thread_proxy_->PostTask(
       FROM_HERE,
       base::Bind(&CallWorkerContextDestroyedOnMainThread,
                  embedded_worker_id_));
 }
 
 void EmbeddedWorkerContextClient::reportException(
     const blink::WebString& error_message,
@@ skipping 115 matching lines @@
 }
 
 void EmbeddedWorkerContextClient::SendWorkerStarted() {
   DCHECK(worker_task_runner_->RunsTasksOnCurrentThread());
   Send(new EmbeddedWorkerHostMsg_WorkerStarted(
       WorkerTaskRunner::Instance()->CurrentWorkerId(),
       embedded_worker_id_));
 }
 
 }  // namespace content