Add a new GetNegotiatedProtocol method to StreamSocket and implement in all subclasses.

BUG=120890

Review URL: https://chromiumcodereview.appspot.com/9958028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@130388 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/socket/client_socket_pool_base_unittest.cc b/net/socket/client_socket_pool_base_unittest.cc
index 6c692fe..d5689c5 100644
--- a/net/socket/client_socket_pool_base_unittest.cc
+++ b/net/socket/client_socket_pool_base_unittest.cc
@@ -117,6 +117,9 @@
         base::TimeDelta::FromMicroseconds(10);
     return kDummyConnectTimeMicros;  // Dummy value.
   }
+  virtual NextProto GetNegotiatedProtocol() const {
+    return kProtoUnknown;
+  }
 
  private:
   bool connected_;