NetworkChangeNotifierMac: lock access to network_reachable_ as it may be read

on different threads than the one on which it's written.

R=eroman@chromium.org


Review URL: http://codereview.chromium.org/7135005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@88389 0039d316-1c4b-4281-b951-d872f2087c98

net/base/network_change_notifier_mac.cc

@@ -10,6 +10,7 @@
 #include <SystemConfiguration/SCSchemaDefinitions.h>
 
 #include "base/mac/scoped_cftyperef.h"
+#include "base/synchronization/lock.h"
 
 namespace net {
 
@@ -27,6 +28,7 @@ NetworkChangeNotifierMac::~NetworkChangeNotifierMac() {
 }
 
 bool NetworkChangeNotifierMac::IsCurrentlyOffline() const {
+  base::AutoLock lock(network_reachable_lock_);
   return !network_reachable_;
 }
 
@@ -120,7 +122,10 @@ void NetworkChangeNotifierMac::ReachabilityCallback(
   bool reachable = flags & kSCNetworkFlagsReachable;
   bool connection_required = flags & kSCNetworkFlagsConnectionRequired;
   bool old_reachability = notifier_mac->network_reachable_;
-  notifier_mac->network_reachable_ = reachable && !connection_required;
+  {
+    base::AutoLock lock(notifier_mac->network_reachable_lock_);
+    notifier_mac->network_reachable_ = reachable && !connection_required;
+  }
   if (old_reachability != notifier_mac->network_reachable_)
     NotifyObserversOfOnlineStateChange();
 }

net/base/network_change_notifier_mac.h

@@ -11,6 +11,7 @@
 
 #include "base/basictypes.h"
 #include "base/mac/scoped_cftyperef.h"
+#include "base/synchronization/lock.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/network_config_watcher_mac.h"
 
@@ -58,6 +59,7 @@ class NetworkChangeNotifierMac: public NetworkChangeNotifier {
   base::mac::ScopedCFTypeRef<CFRunLoopRef> run_loop_;
   base::mac::ScopedCFTypeRef<SCNetworkReachabilityRef> reachability_;
   bool network_reachable_;
+  mutable base::Lock network_reachable_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierMac);
 };