NetworkChangeNotifierMac: synchronize destruction order with helper thread.

Previously, it was possible for NetworkChangeNotifierMac to unschedule
the SCNetworkReachability callback before it had been scheduled.  Under the
hypothesis that this is causing crashes on shutdown, this change makes sure
that the helper thread (on which reachability is initially scheduled) runs to
completion before we check to see if we need to unschedule the callback.

BUG=91767

Review URL: http://codereview.chromium.org/7862006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@100771 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 8 deletions

diff --git a/net/base/network_change_notifier_mac.cc b/net/base/network_change_notifier_mac.cc
index ecf2845..69024c7 100644
--- a/net/base/network_change_notifier_mac.cc
+++ b/net/base/network_change_notifier_mac.cc
@@ -5,12 +5,6 @@
 #include "net/base/network_change_notifier_mac.h"
 
 #include <netinet/in.h>
-#include <SystemConfiguration/SCDynamicStoreKey.h>
-#include <SystemConfiguration/SCNetworkReachability.h>
-#include <SystemConfiguration/SCSchemaDefinitions.h>
-
-#include "base/mac/scoped_cftyperef.h"
-#include "base/synchronization/lock.h"
 
 namespace net {
 
@@ -23,11 +17,19 @@ static bool CalculateReachability(SCNetworkConnectionFlags flags) {
 NetworkChangeNotifierMac::NetworkChangeNotifierMac()
     : online_state_(UNINITIALIZED),
       initial_state_cv_(&online_state_lock_),
-      forwarder_(this),
-      config_watcher_(&forwarder_) {
+      forwarder_(this) {
+  // Must be initialized after the rest of this object, as it may call back into
+  // SetInitialState().
+  config_watcher_.reset(new NetworkConfigWatcherMac(&forwarder_));
 }
 
 NetworkChangeNotifierMac::~NetworkChangeNotifierMac() {
+  // Delete the ConfigWatcher to join the notifier thread, ensuring that
+  // SetDynamicStoreNotificationKeys() has an opportunity to run to completion.
+  config_watcher_.reset();
+
+  // Now that SetDynamicStoreNotificationKeys has either run to completion or
+  // never run at all, unschedule reachability_ if it was previously scheduled.
   if (reachability_.get() && run_loop_.get()) {
     SCNetworkReachabilityUnscheduleFromRunLoop(reachability_.get(),
                                                run_loop_.get(),