Have content/ create and destroy its own threads.

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 18d1d2ba28d8c5418b6001c9377fa6ecffb0985a..163892c540785074dd8ad17cf038235b41bc71e2 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -16,6 +16,7 @@
 #include "base/string_number_conversions.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
+#include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
@@ -316,7 +317,8 @@ class SystemURLRequestContextGetter : public net::URLRequestContextGetter {
 SystemURLRequestContextGetter::SystemURLRequestContextGetter(
     IOThread* io_thread)
     : io_thread_(io_thread),
-      io_message_loop_proxy_(io_thread->message_loop_proxy()) {
+      io_message_loop_proxy_(
+          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)) {
 }
 
 SystemURLRequestContextGetter::~SystemURLRequestContextGetter() {}
@@ -347,8 +349,7 @@ IOThread::IOThread(
     PrefService* local_state,
     ChromeNetLog* net_log,
     ExtensionEventRouterForwarder* extension_event_router_forwarder)
-    : content::BrowserProcessSubThread(BrowserThread::IO),
-      net_log_(net_log),
+    : net_log_(net_log),
       extension_event_router_forwarder_(extension_event_router_forwarder),
       globals_(NULL),
       sdch_manager_(NULL),
@@ -371,17 +372,11 @@ IOThread::IOThread(
                                                     local_state);
   ssl_config_service_manager_.reset(
       SSLConfigServiceManager::CreateDefaultManager(local_state));
-  MessageLoop::current()->PostTask(
-      FROM_HERE, base::Bind(&IOThread::InitSystemRequestContext,
-                            weak_factory_.GetWeakPtr()));
 }
 
 IOThread::~IOThread() {
   if (pref_proxy_config_tracker_.get())
     pref_proxy_config_tracker_->DetachFromPrefService();
-  // We cannot rely on our base class to stop the thread since we want our
-  // CleanUp function to run.
-  Stop();
   DCHECK(!globals_);
 }
 
@@ -402,14 +397,12 @@ net::URLRequestContextGetter* IOThread::system_url_request_context_getter() {
   return system_url_request_context_getter_;
 }
 
-void IOThread::Init() {
+void IOThread::InitializeGlobalState() {
   // 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);
 
-  content::BrowserProcessSubThread::Init();
-
-  DCHECK_EQ(MessageLoop::TYPE_IO, message_loop()->type());
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
 #if defined(USE_NSS)
   net::SetMessageLoopForOCSP();
@@ -480,9 +473,16 @@ void IOThread::Init() {
 
   sdch_manager_ = new net::SdchManager();
   sdch_manager_->set_sdch_fetcher(new SdchDictionaryFetcher);
+
+  // The io_thread_ object is guaranteed to outlive the thread, as
+  // it is destroyed only during the call to PostStopThread(IO),
+  // at which point the IO thread has stopped.
+  //message_loop()->AddDestructionObserver(this);
 }
 
-void IOThread::CleanUp() {
+void IOThread::WillDestroyCurrentMessageLoop() {
+  MessageLoop::current()->RemoveDestructionObserver(this);
+
   delete sdch_manager_;
   sdch_manager_ = NULL;
 
@@ -520,10 +520,6 @@ void IOThread::CleanUp() {
   base::debug::LeakTracker<net::URLRequest>::CheckForLeaks();
 
   base::debug::LeakTracker<SystemURLRequestContextGetter>::CheckForLeaks();
-
-  // This will delete the |notification_service_|.  Make sure it's done after
-  // anything else can reference it.
-  content::BrowserProcessSubThread::CleanUp();
 }
 
 // static
@@ -574,6 +570,11 @@ void IOThread::ClearHostCache() {
     host_cache->clear();
 }
 
+MessageLoop* IOThread::message_loop() const {
+  return BrowserThread::UnsafeGetBrowserThread(
+      BrowserThread::IO)->message_loop();
+}
+
 net::SSLConfigService* IOThread::GetSSLConfigService() {
   return ssl_config_service_manager_->Get();
 }