[chromecast] Slew stream volume changes in StreamMixerAlsa.

chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc

Index: chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc
diff --git a/chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc b/chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc
index 14a12641ca7230eab8e955af2d1765d2674e4095..a3aaa2536044451fca1d3d0d1f9a6222d87c0f24 100644
--- a/chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc
+++ b/chromecast/media/cma/backend/alsa/stream_mixer_alsa_unittest.cc
@@ -143,7 +143,6 @@ class MockInputQueue : public StreamMixerAlsa::InputQueue {
 
   // StreamMixerAlsa::InputQueue implementation:
   int input_samples_per_second() const override { return samples_per_second_; }
-  float volume_multiplier() const override { return multiplier_; }
   bool primary() const override { return primary_; }
   bool IsDeleting() const override { return deleting_; }
   MOCK_METHOD1(Initialize,