Disallow UI/IO thread blocking on any other thread.

content/browser/browser_process_sub_thread.cc

 // Copyright (c) 2011 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/browser/browser_process_sub_thread.h"
 
 #if defined(OS_WIN)
 #include <Objbase.h>
 #endif
 
 #include "base/debug/leak_tracker.h"
+#include "base/threading/thread_restrictions.h"
 #include "build/build_config.h"
 #include "content/browser/browser_child_process_host_impl.h"
 #include "content/browser/in_process_webkit/indexed_db_key_utility_client.h"
 #include "content/browser/notification_service_impl.h"
 #include "content/public/common/url_fetcher.h"
 #include "net/url_request/url_request.h"
 
 namespace content {
 
 BrowserProcessSubThread::BrowserProcessSubThread(BrowserThread::ID identifier)
     : BrowserThreadImpl(identifier),
       notification_service_(NULL) {
 }
 
 BrowserProcessSubThread::~BrowserProcessSubThread() {
   Stop();
 }
 
 void BrowserProcessSubThread::Init() {
 #if defined(OS_WIN)
   // Initializes the COM library on the current thread.
   CoInitialize(NULL);
 #endif
 
   notification_service_ = new NotificationServiceImpl;
 
   BrowserThreadImpl::Init();
+
+  if (BrowserThread::CurrentlyOn(BrowserThread::IO)) {
+    // Though this thread is called the "IO" thread, it actually just routes
+    // messages around; it shouldn't be allowed to perform any blocking disk
+    // I/O.
+    base::ThreadRestrictions::SetIOAllowed(false);
+    base::ThreadRestrictions::DisallowWaiting();
+  }
 }
 
 void BrowserProcessSubThread::CleanUp() {
   if (BrowserThread::CurrentlyOn(BrowserThread::IO))
     IOThreadPreCleanUp();
 
   BrowserThreadImpl::CleanUp();
 
   if (BrowserThread::CurrentlyOn(BrowserThread::IO))
     IOThreadPostCleanUp();
@@ skipping 22 matching lines @@
   // IO thread only resources they are referencing.
   BrowserChildProcessHostImpl::TerminateAll();
 }
 
 void BrowserProcessSubThread::IOThreadPostCleanUp() {
   // net::URLRequest instances must NOT outlive the IO thread.
   base::debug::LeakTracker<net::URLRequest>::CheckForLeaks();
 }
 
 }  // namespace content