Remove DestructionObserver for NetworkConfigWatcherMac.

net/base/network_config_watcher_mac.cc

Index: net/base/network_config_watcher_mac.cc
diff --git a/net/base/network_config_watcher_mac.cc b/net/base/network_config_watcher_mac.cc
index 365859e275e025a78758afb6dabdf45406219d53..dd93067c7d275c397a4c864b0d36812c6affacf3 100644
--- a/net/base/network_config_watcher_mac.cc
+++ b/net/base/network_config_watcher_mac.cc
@@ -8,12 +8,10 @@
 #include <SystemConfiguration/SCSchemaDefinitions.h>
 #include <algorithm>
 
+#include "base/compiler_specific.h"
 #include "base/thread.h"
 #include "base/mac/scoped_cftyperef.h"
 
-// We only post tasks to a child thread we own, so we don't need refcounting.
-DISABLE_RUNNABLE_METHOD_REFCOUNT(net::NetworkConfigWatcherMac);
-
 namespace net {
 
 namespace {
@@ -27,48 +25,59 @@ void DynamicStoreCallback(SCDynamicStoreRef /* store */,
   net_config_delegate->OnNetworkConfigChange(changed_keys);
 }
 
-}  // namespace
+class NetworkConfigWatcherMacThread : public base::Thread {
+ public:
+  NetworkConfigWatcherMacThread(NetworkConfigWatcherMac::Delegate* delegate);
+  virtual ~NetworkConfigWatcherMacThread();
 
-NetworkConfigWatcherMac::NetworkConfigWatcherMac(
-    Delegate* delegate)
-    : notifier_thread_(new base::Thread("NetworkConfigWatcher")),
-      delegate_(delegate) {
-  // We create this notifier thread because the notification implementation
-  // needs a thread with a CFRunLoop, and there's no guarantee that
-  // MessageLoop::current() meets that criterion.
-  base::Thread::Options thread_options(MessageLoop::TYPE_UI, 0);
-  notifier_thread_->StartWithOptions(thread_options);
+ protected:
+  // base::Thread
+  virtual void Init();
+  virtual void CleanUp();
+
+ private:
+  // The SystemConfiguration calls in this function can lead to contention early
+  // on, so we invoke this function later on in startup to keep it fast.
+  void InitNotifications();
+
+  base::mac::ScopedCFTypeRef<CFRunLoopSourceRef> run_loop_source_;
+  NetworkConfigWatcherMac::Delegate* const delegate_;
+  ScopedRunnableMethodFactory<NetworkConfigWatcherMacThread> method_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkConfigWatcherMacThread);
+};
+
+NetworkConfigWatcherMacThread::NetworkConfigWatcherMacThread(
+    NetworkConfigWatcherMac::Delegate* delegate)
+    : base::Thread("NetworkConfigWatcher"),
+      delegate_(delegate),
+      ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {}
+
+NetworkConfigWatcherMacThread::~NetworkConfigWatcherMacThread() {
+  Stop();
+}
+
+void NetworkConfigWatcherMacThread::Init() {
   // TODO(willchan): Look to see if there's a better signal for when it's ok to
   // initialize this, rather than just delaying it by a fixed time.
-  const int kNotifierThreadInitializationDelayMS = 1000;
-  notifier_thread_->message_loop()->PostDelayedTask(
+  const int kInitializationDelayMS = 1000;
+  message_loop()->PostDelayedTask(
       FROM_HERE,
-      NewRunnableMethod(this, &NetworkConfigWatcherMac::Init),
-      kNotifierThreadInitializationDelayMS);
-}
-
-NetworkConfigWatcherMac::~NetworkConfigWatcherMac() {
-  // We don't need to explicitly Stop(), but doing so allows us to sanity-
-  // check that the notifier thread shut down properly.
-  notifier_thread_->Stop();
-  DCHECK(run_loop_source_ == NULL);
+      method_factory_.NewRunnableMethod(
+          &NetworkConfigWatcherMacThread::InitNotifications),
+      kInitializationDelayMS);
 }
 
-void NetworkConfigWatcherMac::WillDestroyCurrentMessageLoop() {
-  DCHECK(notifier_thread_ != NULL);
-  // We can't check the notifier_thread_'s message_loop(), as it's now 0.
-  // DCHECK_EQ(notifier_thread_->message_loop(), MessageLoop::current());
+void NetworkConfigWatcherMacThread::CleanUp() {
+  if (!run_loop_source_.get())
+    return;
 
-  DCHECK(run_loop_source_ != NULL);
   CFRunLoopRemoveSource(CFRunLoopGetCurrent(), run_loop_source_.get(),
                         kCFRunLoopCommonModes);
   run_loop_source_.reset();
 }
 
-void NetworkConfigWatcherMac::Init() {
-  DCHECK(notifier_thread_ != NULL);
-  DCHECK_EQ(notifier_thread_->message_loop(), MessageLoop::current());
-
+void NetworkConfigWatcherMacThread::InitNotifications() {
   // Add a run loop source for a dynamic store to the current run loop.
   SCDynamicStoreContext context = {
     0,          // Version 0.
@@ -86,8 +95,19 @@ void NetworkConfigWatcherMac::Init() {
 
   // Set up notifications for interface and IP address changes.
   delegate_->SetDynamicStoreNotificationKeys(store.get());
+}
+
+}  // namespace
 
-  MessageLoop::current()->AddDestructionObserver(this);
+NetworkConfigWatcherMac::NetworkConfigWatcherMac(Delegate* delegate)
+    : notifier_thread_(new NetworkConfigWatcherMacThread(delegate)) {
+  // We create this notifier thread because the notification implementation
+  // needs a thread with a CFRunLoop, and there's no guarantee that
+  // MessageLoop::current() meets that criterion.
+  base::Thread::Options thread_options(MessageLoop::TYPE_UI, 0);
+  notifier_thread_->StartWithOptions(thread_options);
 }
 
+NetworkConfigWatcherMac::~NetworkConfigWatcherMac() {}
+
 }  // namespace net