Smooth BWE and pass it to Audio Network Adaptor.

webrtc/common_audio/mocks/mock_smoothing_filter.h

Index: webrtc/common_audio/mocks/mock_smoothing_filter.h
diff --git a/webrtc/common_audio/mocks/mock_smoothing_filter.h b/webrtc/common_audio/mocks/mock_smoothing_filter.h
index 6b2991b22f91d736fa1e5849fc94d5b8573716db..171a8ca57455fd530e27e4664b78f5162494da14 100644
--- a/webrtc/common_audio/mocks/mock_smoothing_filter.h
+++ b/webrtc/common_audio/mocks/mock_smoothing_filter.h
@@ -20,6 +20,7 @@ class MockSmoothingFilter : public SmoothingFilter {
  public:
   MOCK_METHOD1(AddSample, void(float));
   MOCK_CONST_METHOD0(GetAverage, rtc::Optional<float>());
+  MOCK_METHOD1(SetTimeConstantMs, void(int));
 };
 
 }  // namespace webrtc