Add 16-bit network id to the candidate signaling.
Also include that in the stun-ping request as part of the
network-info attribute.
Change the network cost to be 16 bits.

BUG=

Review URL: https://codereview.webrtc.org/1815473002

Cr-Commit-Position: refs/heads/master@{#12110}
diff --git a/webrtc/api/webrtcsdp.cc b/webrtc/api/webrtcsdp.cc
index 4a296d9..93d4acc 100644
--- a/webrtc/api/webrtcsdp.cc
+++ b/webrtc/api/webrtcsdp.cc
@@ -127,6 +127,7 @@
 static const char kAttributeCandidateUfrag[] = "ufrag";
 static const char kAttributeCandidatePwd[] = "pwd";
 static const char kAttributeCandidateGeneration[] = "generation";
+static const char kAttributeCandidateNetworkId[] = "network-id";
 static const char kAttributeCandidateNetworkCost[] = "network-cost";
 static const char kAttributeFingerprint[] = "fingerprint";
 static const char kAttributeSetup[] = "setup";
@@ -1092,7 +1093,8 @@
   std::string username;
   std::string password;
   uint32_t generation = 0;
-  uint32_t network_cost = 0;
+  uint16_t network_id = 0;
+  uint16_t network_cost = 0;
   for (size_t i = current_position; i + 1 < fields.size(); ++i) {
     // RFC 5245
     // *(SP extension-att-name SP extension-att-value)
@@ -1104,10 +1106,15 @@
       username = fields[++i];
     } else if (fields[i] == kAttributeCandidatePwd) {
       password = fields[++i];
+    } else if (fields[i] == kAttributeCandidateNetworkId) {
+      if (!GetValueFromString(first_line, fields[++i], &network_id, error)) {
+        return false;
+      }
     } else if (fields[i] == kAttributeCandidateNetworkCost) {
       if (!GetValueFromString(first_line, fields[++i], &network_cost, error)) {
         return false;
       }
+      network_cost = std::min(network_cost, cricket::kMaxNetworkCost);
     } else {
       // Skip the unknown extension.
       ++i;
@@ -1116,10 +1123,9 @@
 
   *candidate = Candidate(component_id, cricket::ProtoToString(protocol),
                          address, priority, username, password, candidate_type,
-                         generation, foundation);
+                         generation, foundation, network_id, network_cost);
   candidate->set_related_address(related_address);
   candidate->set_tcptype(tcptype);
-  candidate->set_network_cost(std::min(network_cost, cricket::kMaxNetworkCost));
   return true;
 }
 
@@ -1814,6 +1820,9 @@
     if (include_ufrag && !it->username().empty()) {
       os << " " << kAttributeCandidateUfrag << " " << it->username();
     }
+    if (it->network_id() > 0) {
+      os << " " << kAttributeCandidateNetworkId << " " << it->network_id();
+    }
     if (it->network_cost() > 0) {
       os << " " << kAttributeCandidateNetworkCost << " " << it->network_cost();
     }
diff --git a/webrtc/api/webrtcsdp_unittest.cc b/webrtc/api/webrtcsdp_unittest.cc
index 9559701..c527204 100644
--- a/webrtc/api/webrtcsdp_unittest.cc
+++ b/webrtc/api/webrtcsdp_unittest.cc
@@ -2058,6 +2058,19 @@
                                          candidate_with_ufrag));
   message = webrtc::SdpSerializeCandidate(*jcandidate_);
   EXPECT_EQ(std::string(kRawCandidate) + " ufrag ABC", message);
+
+  Candidate candidate_with_network_info(candidates_.front());
+  candidate_with_network_info.set_network_id(1);
+  jcandidate_.reset(new JsepIceCandidate(std::string("audio"), 0,
+                                         candidate_with_network_info));
+  message = webrtc::SdpSerializeCandidate(*jcandidate_);
+  EXPECT_EQ(std::string(kRawCandidate) + " network-id 1", message);
+  candidate_with_network_info.set_network_cost(999);
+  jcandidate_.reset(new JsepIceCandidate(std::string("audio"), 0,
+                                         candidate_with_network_info));
+  message = webrtc::SdpSerializeCandidate(*jcandidate_);
+  EXPECT_EQ(std::string(kRawCandidate) + " network-id 1 network-cost 999",
+            message);
 }
 
 // TODO(mallinath) : Enable this test once WebRTCSdp capable of parsing
@@ -2325,6 +2338,7 @@
   EXPECT_EQ(kDummyMid, jcandidate.sdp_mid());
   EXPECT_EQ(kDummyIndex, jcandidate.sdp_mline_index());
   EXPECT_TRUE(jcandidate.candidate().IsEquivalent(jcandidate_->candidate()));
+  EXPECT_EQ(0, jcandidate.candidate().network_cost());
 
   // Candidate line without generation extension.
   sdp = kSdpOneCandidate;
@@ -2336,6 +2350,22 @@
   expected.set_generation(0);
   EXPECT_TRUE(jcandidate.candidate().IsEquivalent(expected));
 
+  // Candidate with network id and/or cost.
+  sdp = kSdpOneCandidate;
+  Replace(" generation 2", " generation 2 network-id 2", &sdp);
+  EXPECT_TRUE(SdpDeserializeCandidate(sdp, &jcandidate));
+  EXPECT_EQ(kDummyMid, jcandidate.sdp_mid());
+  EXPECT_EQ(kDummyIndex, jcandidate.sdp_mline_index());
+  expected = jcandidate_->candidate();
+  expected.set_network_id(2);
+  EXPECT_TRUE(jcandidate.candidate().IsEquivalent(expected));
+  EXPECT_EQ(0, jcandidate.candidate().network_cost());
+  // Add network cost
+  Replace(" network-id 2", " network-id 2 network-cost 9", &sdp);
+  EXPECT_TRUE(SdpDeserializeCandidate(sdp, &jcandidate));
+  EXPECT_TRUE(jcandidate.candidate().IsEquivalent(expected));
+  EXPECT_EQ(9, jcandidate.candidate().network_cost());
+
   sdp = kSdpTcpActiveCandidate;
   EXPECT_TRUE(SdpDeserializeCandidate(sdp, &jcandidate));
   // Make a cricket::Candidate equivalent to kSdpTcpCandidate string.