Add 16-bit network id to the candidate signaling.

webrtc/base/network.h

Index: webrtc/base/network.h
diff --git a/webrtc/base/network.h b/webrtc/base/network.h
index 680c005ea29ace284f9aae3c7bf4c07f9694f6a0..ba3153e2624fb5cb5e48ba6d8f8cb76fe15baa25 100644
--- a/webrtc/base/network.h
+++ b/webrtc/base/network.h
@@ -173,6 +173,7 @@ class NetworkManagerBase : public NetworkManager {
 
   IPAddress default_local_ipv4_address_;
   IPAddress default_local_ipv6_address_;
+  uint16_t next_available_network_id_ = 1;

[pthatcher1, 2016/03/21 17:49:24]

We should probably make a comment that we're OK with this rolling over, and why.

[honghaiz3, 2016/03/22 16:30:03]

Done.

 };
 
 // Basic implementation of the NetworkManager interface that gets list
@@ -339,6 +340,11 @@ class Network {
   AdapterType type() const { return type_; }
   void set_type(AdapterType type) { type_ = type; }
 
+  // A unique id assigned by the network manager, which may be signaled
+  // to the remote side in the candidate.
+  uint16_t id() const { return id_; }
+  void set_id(uint16_t id) { id_ = id; }
+
   int preference() const { return preference_; }
   void set_preference(int preference) { preference_ = preference; }
 
@@ -372,6 +378,7 @@ class Network {
   AdapterType type_;
   int preference_;
   bool active_ = true;
+  uint16_t id_ = 0;
 
   friend class NetworkManager;
 };