Open backdoor in VoiceEngineImpl to get at the actual voe::Channel objects from an ID.

webrtc/test/mock_voice_engine.h

Index: webrtc/test/mock_voice_engine.h
diff --git a/webrtc/test/mock_voice_engine.h b/webrtc/test/mock_voice_engine.h
index dead2260a37625e8a55eeebd468e0d0dc8c20844..28a75f806398645bea70c838b93580675cb35219 100644
--- a/webrtc/test/mock_voice_engine.h
+++ b/webrtc/test/mock_voice_engine.h
@@ -12,6 +12,7 @@
 #define WEBRTC_AUDIO_MOCK_VOICE_ENGINE_H_
 
 #include "testing/gmock/include/gmock/gmock.h"
+#include "webrtc/test/mock_voe_channel_proxy.h"
 #include "webrtc/voice_engine/voice_engine_impl.h"
 
 namespace webrtc {
@@ -25,12 +26,26 @@ class MockVoiceEngine : public VoiceEngineImpl {
     // Increase ref count so this object isn't automatically deleted whenever
     // interfaces are Release():d.
     ++_ref_count;
+    // We add this default behavior to make the mock easier to use in tests. It
+    // will create a NiceMock of a voe::ChannelProxy.
+    ON_CALL(*this, ChannelProxyFactory(testing::_))
+        .WillByDefault(
+            testing::Invoke([](int channel_id) {
+              return new testing::NiceMock<MockVoEChannelProxy>();
+            }));
   }
   ~MockVoiceEngine() override {
     // Decrease ref count before base class d-tor is called; otherwise it will
     // trigger an assertion.
     --_ref_count;
   }
+  // Allows injecting a ChannelProxy factory.
+  MOCK_METHOD1(ChannelProxyFactory, voe::ChannelProxy*(int channel_id));
+
+  // VoiceEngineImpl
+  rtc::scoped_ptr<voe::ChannelProxy> GetChannelProxy(int channel_id) override {
+    return rtc::scoped_ptr<voe::ChannelProxy>(ChannelProxyFactory(channel_id));
+  }
 
   // VoEAudioProcessing
   MOCK_METHOD2(SetNsStatus, int(bool enable, NsModes mode));