Adding error enum to be used by PeerConnectionInterface methods.

webrtc/api/peerconnectioninterface_unittest.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include <memory>
+#include <sstream>
 #include <string>
 #include <utility>
 
 #include "webrtc/api/audiotrack.h"
 #include "webrtc/api/jsepsessiondescription.h"
 #include "webrtc/api/mediastream.h"
 #include "webrtc/api/mediastreaminterface.h"
 #include "webrtc/api/peerconnection.h"
 #include "webrtc/api/peerconnectioninterface.h"
 #include "webrtc/api/rtpreceiverinterface.h"
@@ skipping 2960 matching lines @@
   FakeConstraints updated_answer_c;
   answer_c.SetMandatoryReceiveAudio(false);
   answer_c.SetMandatoryReceiveVideo(false);
 
   cricket::MediaSessionOptions updated_answer_options;
   EXPECT_TRUE(
       ParseConstraintsForAnswer(&updated_answer_c, &updated_answer_options));
   EXPECT_TRUE(updated_answer_options.has_audio());
   EXPECT_TRUE(updated_answer_options.has_video());
 }
+
+TEST(RtcErrorTest, OstreamOperator) {
+  std::ostringstream oss;
+  oss << webrtc::RtcError::NONE << ' '
+      << webrtc::RtcError::INVALID_PARAMETER << ' '
+      << webrtc::RtcError::INTERNAL_ERROR;
+  EXPECT_EQ("NONE INVALID_PARAMETER INTERNAL_ERROR", oss.str());
+}