[NetworkChangeNotifier] Return more specific network connection types (ethernet/wifi) on OSX

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 24eaee9015f3cd10303ce130920a63f14623bc02..bc46c120640c98f51f79e5038c43eef0c44a61e6 100644
--- a/net/base/network_config_watcher_mac.cc
+++ b/net/base/network_config_watcher_mac.cc
@@ -67,10 +67,7 @@ NetworkConfigWatcherMacThread::~NetworkConfigWatcherMacThread() {
 }
 
 void NetworkConfigWatcherMacThread::Init() {
-  // Disallow IO to make sure NetworkConfigWatcherMacThread's helper thread does
-  // not perform blocking operations.
-  base::ThreadRestrictions::SetIOAllowed(false);
-
+  base::ThreadRestrictions::SetIOAllowed(true);
   delegate_->Init();
 
   // TODO(willchan): Look to see if there's a better signal for when it's ok to