Use supported Android network handles in Android M and newer.

net/base/network_change_notifier.h

Index: net/base/network_change_notifier.h
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index aafee7a20067ed50206a7505ad2fcfd444d85451..27a798d04d1fcf6d2714904324d31e26d18059bd 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -211,8 +211,11 @@ class NET_EXPORT NetworkChangeNotifier {
   // example an association with a particular WiFi network with a particular
   // SSID or a connection to particular cellular network.
   // The meaning of this handle is target-dependent. On Android NetworkHandles
-  // are equivalent to the framework's concept of NetIDs (e.g. Network.netId).
-  typedef int32_t NetworkHandle;
+  // are equivalent to:
+  //   On Lollipop, the framework's concept of NetIDs (e.g. Network.netId), and
+  //   On Marshmallow and newer releases, network handles
+  //           (e.g. Network.getNetworkHandle()).
+  typedef int64_t NetworkHandle;
 
   // A list of networks.
   typedef std::vector<NetworkHandle> NetworkList;