Update the type and cost of existing networks if its type is found later by network monitor

webrtc/base/network.h

Index: webrtc/base/network.h
diff --git a/webrtc/base/network.h b/webrtc/base/network.h
index a41da4a69a0f01f41fd7344ce89d99b6f0e593d2..2bd280976386bb743d5c16ebdc76fde234c944a6 100644
--- a/webrtc/base/network.h
+++ b/webrtc/base/network.h
@@ -37,6 +37,8 @@ class Network;
 class NetworkMonitorInterface;
 class Thread;
 
+static const uint16_t kMaxNetworkCost = 999;
+static const uint16_t kNetworkCostForUnknownType = 10;

[pthatcher1, 2016/05/17 21:23:11]

See my comments about these names in another CL (I'd prefer something like
kNetworkCostMin = 0,  kNetworkCostLow = 10, kNetworkCostUnknown = 50, 
kNetworkCostHigh = 900, kNetworkCostMax = 999).

[honghaiz3, 2016/05/18 07:41:46]

Done. I once worried that one client may set its cellular cost to be 901 so that
his cellular will be less used than the other side. 
So I set the cellular cost to the maximum vale 999. 
But since webrtc is controlling the cost assignment on both sides, it is perhaps
OK to assign it to 900. 
Let me know if you think this may be an issue. 

 
 // By default, ignore loopback interfaces on the host.
 const int kDefaultNetworkIgnoreMask = ADAPTER_TYPE_LOOPBACK;
@@ -249,6 +251,8 @@ class BasicNetworkManager : public NetworkManagerBase,
   // Only updates the networks; does not reschedule the next update.
   void UpdateNetworksOnce();
 
+  AdapterType GetAdapterTypeFromName(const char* network_name) const;
+
   Thread* thread_;
   bool sent_first_update_;
   int start_count_;
@@ -273,6 +277,7 @@ class Network {
   ~Network();
 
   sigslot::signal1<const Network*> SignalInactive;
+  sigslot::signal1<const Network*> SignalNetworkTypeChanged;

[pthatcher1, 2016/05/17 21:23:11]

SignalTypeChanged would be enough, since this is a Network.

[honghaiz3, 2016/05/18 07:41:46]

Done.

 
   const DefaultLocalAddressProvider* default_local_address_provider() {
     return default_local_address_provider_;
@@ -344,7 +349,23 @@ class Network {
   void set_ignored(bool ignored) { ignored_ = ignored; }
 
   AdapterType type() const { return type_; }
-  void set_type(AdapterType type) { type_ = type; }
+  void set_type(AdapterType type) {
+    if (type_ != type) {

[pthatcher1, 2016/05/17 21:23:11]

I'd slightly prefer this with an early return:

if (type_ == type) {
  return;
}

type_ = type;
SignalTypeChanged(this);

[honghaiz3, 2016/05/18 07:41:46]

Done.

+      type_ = type;
+      SignalNetworkTypeChanged(this);
+    }
+  }
+
+  uint16_t GetCost() const {
+    switch (type_) {
+      case rtc::ADAPTER_TYPE_UNKNOWN:
+        return kNetworkCostForUnknownType;
+      case rtc::ADAPTER_TYPE_CELLULAR:
+        return kMaxNetworkCost;
+      default:

[pthatcher1, 2016/05/17 21:23:11]

Again, see my comments in the other CL where I think the default should be
"UNKNOWN" and we should enumerate wifi/ethernet, and should prefer ethernet
slightly over wifi.

[honghaiz3, 2016/05/18 07:41:46]

Done.

+        return 0;
+    }
+  }
 
   // A unique id assigned by the network manager, which may be signaled
   // to the remote side in the candidate.