Implemented the GetSources() in native code.

webrtc/test/mock_voe_channel_proxy.h

 /*
  *  Copyright (c) 2015 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.
  */
 
 #ifndef WEBRTC_TEST_MOCK_VOE_CHANNEL_PROXY_H_
 #define WEBRTC_TEST_MOCK_VOE_CHANNEL_PROXY_H_
 
 #include <string>
 
+#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 #include "webrtc/test/gmock.h"
 #include "webrtc/voice_engine/channel_proxy.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 
 namespace webrtc {
 namespace test {
 
 class MockVoEChannelProxy : public voe::ChannelProxy {
  public:
   MOCK_METHOD1(SetRTCPStatus, void(bool enable));
   MOCK_METHOD1(SetLocalSSRC, void(uint32_t ssrc));
   MOCK_METHOD1(SetRTCP_CNAME, void(const std::string& c_name));
   MOCK_METHOD2(SetNACKStatus, void(bool enable, int max_packets));
@@ skipping 55 matching lines @@
   MOCK_METHOD1(SetOpusDtx, bool(bool enable));
   MOCK_METHOD1(SetOpusMaxPlaybackRate, bool(int frequency_hz));
   MOCK_METHOD1(SetSendCodec, bool(const CodecInst& codec_inst));
   MOCK_METHOD2(SetSendCNPayloadType,
                bool(int type, PayloadFrequencies frequency));
   MOCK_METHOD1(SetReceiveCodecs,
                void(const std::map<int, SdpAudioFormat>& codecs));
   MOCK_METHOD1(OnTwccBasedUplinkPacketLossRate, void(float packet_loss_rate));
   MOCK_METHOD1(OnRecoverableUplinkPacketLossRate,
                void(float recoverable_packet_loss_rate));
+  MOCK_CONST_METHOD0(GetSources, std::vector<RtpSource>());
 };
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_TEST_MOCK_VOE_CHANNEL_PROXY_H_