Implemented the GetSources() in native code.

webrtc/test/mock_voe_channel_proxy.h

Index: webrtc/test/mock_voe_channel_proxy.h
diff --git a/webrtc/test/mock_voe_channel_proxy.h b/webrtc/test/mock_voe_channel_proxy.h
index b62c266ff696177aceadac0c64b34f071f2345a2..ad53f26169757f516bcf6d6d04ecb6b04ea8da67 100644
--- a/webrtc/test/mock_voe_channel_proxy.h
+++ b/webrtc/test/mock_voe_channel_proxy.h
@@ -13,9 +13,10 @@
 
 #include <string>
 
+#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 #include "webrtc/test/gmock.h"
+#include "webrtc/voice_engine/channel.h"

[the sun, 2017/04/05 14:58:30]

No, do not include voice_engine/channel.h here. In fact, since this is mocking
methods already declared in voice_engine/channel_proxy.h, we should be able to
rely on transient includes from there.

[Zhi Huang, 2017/04/06 03:09:50]

Done.

 #include "webrtc/voice_engine/channel_proxy.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 
 namespace webrtc {
 namespace test {
@@ -91,6 +92,7 @@ class MockVoEChannelProxy : public voe::ChannelProxy {
   MOCK_METHOD1(OnTwccBasedUplinkPacketLossRate, void(float packet_loss_rate));
   MOCK_METHOD1(OnRecoverableUplinkPacketLossRate,
                void(float recoverable_packet_loss_rate));
+  MOCK_METHOD0(GetSources, const std::vector<RtpSource>());
 };
 }  // namespace test
 }  // namespace webrtc