Allow an external audio processing module to be used in WebRTC

webrtc/voice_engine/voice_engine_fixture.cc

Index: webrtc/voice_engine/voice_engine_fixture.cc
diff --git a/webrtc/voice_engine/voice_engine_fixture.cc b/webrtc/voice_engine/voice_engine_fixture.cc
index faac8dd48c254af46ddc30f1638fb2da16d9fb0c..3cb613d0ba85a0ae3611c51ac565f3014d3e1c81 100644
--- a/webrtc/voice_engine/voice_engine_fixture.cc
+++ b/webrtc/voice_engine/voice_engine_fixture.cc
@@ -9,6 +9,7 @@
  */
 
 #include "webrtc/voice_engine/voice_engine_fixture.h"
+#include "webrtc/modules/audio_processing/include/mock_audio_processing.h"
 
 namespace webrtc {
 
@@ -19,6 +20,7 @@ VoiceEngineFixture::VoiceEngineFixture()
   EXPECT_NE(nullptr, base_);
   EXPECT_NE(nullptr, network_);
   EXPECT_EQ(0, base_->RegisterVoiceEngineObserver(observer_));
+  apm_ = new rtc::RefCountedObject<test::MockAudioProcessing>();
 }
 
 VoiceEngineFixture::~VoiceEngineFixture() {