Kill worker process by way of a sync IPC message before it cleans up.

content/worker/worker_thread.cc

 // Copyright (c) 2012 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/worker/worker_thread.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/threading/thread_local.h"
 #include "content/child/appcache/appcache_dispatcher.h"
@@ skipping 38 matching lines @@
   channel()->AddFilter(db_message_filter_.get());
 
   indexed_db_message_filter_ = new IndexedDBMessageFilter(
       thread_safe_sender());
   channel()->AddFilter(indexed_db_message_filter_.get());
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   SetRuntimeFeaturesDefaultsAndUpdateFromArgs(command_line);
 }
 
+void WorkerThread::OnProcessFinalRelease() {
+  // The worker process is to be shut down gracefully. Ask the browser
+  // process to shut it down forcefully instead and wait on the message, so that
+  // there are no races between threads when the process is shutting down.
+  Send(new WorkerProcessHostMsg_ForceKillWorker());

[michaeln, 2013/09/16 22:00:41]

Does it not work to have this line as the first and only line of
WorkerThread::Shutdown?

In the 'final release' sequence, there's an opportunity for the browser process
to change its mind about shutting down the  child afterall. With current code,
when WorkerProcessHost::CanShutdown() returns false, the 'final release' doesn't
result in a shutdown. This CL changes that behavior and will kill the process
even if CanShutdown says 'false'. Not sure we want that behavior change.

[Mustafa Acer, 2013/09/16 22:08:44]

It doesn't work.
How about overriding ChildThread::OnShutdown then? That should be called after
the browser says that the process can be shut down.

+}
+
 WorkerThread::~WorkerThread() {
 }
 
 void WorkerThread::Shutdown() {
   ChildThread::Shutdown();
 
   // Shutdown in reverse of the initialization order.
   channel()->RemoveFilter(indexed_db_message_filter_.get());
   indexed_db_message_filter_ = NULL;
 
@@ skipping 43 matching lines @@
 
 void WorkerThread::RemoveWorkerStub(WebSharedWorkerStub* stub) {
   worker_stubs_.erase(stub);
 }
 
 void WorkerThread::AddWorkerStub(WebSharedWorkerStub* stub) {
   worker_stubs_.insert(stub);
 }
 
 }  // namespace content