Add instrumentation to track the IceEndpointType.

webrtc/p2p/base/candidate.h

Index: webrtc/p2p/base/candidate.h
diff --git a/webrtc/p2p/base/candidate.h b/webrtc/p2p/base/candidate.h
index c2b889541e72165461c9a2f4055dd14d9b73651b..7e05f602ae07cfdd2d228ff135f8bfe7134956a7 100644
--- a/webrtc/p2p/base/candidate.h
+++ b/webrtc/p2p/base/candidate.h
@@ -70,6 +70,18 @@ class Candidate {
   const std::string & protocol() const { return protocol_; }
   void set_protocol(const std::string & protocol) { protocol_ = protocol; }
 
+  // The protocol used by the first hop. Mainly interesting for TURN/TCP
+  // candidate as it's actually TCP although the candidate is udp itself.
+  const std::string& first_hop_protocol() const {

[juberti1, 2015/08/14 21:04:59]

Rather than duplicating the protocol value in cases where there is only one hop
(e.g. host, srflx), I suggest making this relay_protocol(), and leaving it empty
for non-relay candidates. (Similar to how tcptype is left empty for non-tcp
candidates.)

+    if (first_hop_protocol_.empty()) {
+      return protocol_;
+    }
+    return first_hop_protocol_;
+  }
+  void set_first_hop_protocol(const std::string& protocol) {
+    first_hop_protocol_ = protocol;
+  }
+
   const rtc::SocketAddress & address() const { return address_; }
   void set_address(const rtc::SocketAddress & address) {
     address_ = address;
@@ -214,6 +226,7 @@ class Candidate {
   std::string id_;
   int component_;
   std::string protocol_;
+  std::string first_hop_protocol_;
   rtc::SocketAddress address_;
   uint32 priority_;
   std::string username_;