Remove voe::TransmitMixer

TransmitMixer's functionality is moved into the AudioTransportProxy
owned by AudioState. This removes the need for an AudioTransport
implementation in VoEBaseImpl, which means that the proxy is no longer
a proxy, hence AudioTransportProxy is renamed to AudioTransportImpl.

In the short term, AudioState needs to know which AudioDeviceModule is
used, so it is added in AudioState::Config. AudioTransportImpl needs
to know which AudioSendStream:s are currently enabled to send, so
AudioState maintains a map of them, which is reduced into a simple
vector for AudioTransportImpl.

To encode and transmit audio,
AudioSendStream::OnAudioData(std::unique_ptr<AudioFrame> audio_frame)
is introduced, which is used in both the Chromium and standalone use
cases. This removes the need for two different instances of
voe::Channel::ProcessAndEncodeAudio(), so there is now only one,
taking an AudioFrame as argument. Callers need to allocate their own
AudioFrame:s, which is wasteful but not a regression since this was
already happening in the voe::Channel functions.

Most of the logic changed resides in
AudioTransportImpl::RecordedDataIsAvailable(), where two strange
things were found:

  1. The clock drift parameter was ineffective since
     apm->echo_cancellation()->enable_drift_compensation(false) is
     called during initialization.

  2. The output parameter 'new_mic_volume' was never set - instead it
     was returned as a result, causing the ADM to never update the
     analog mic gain
     (https://cs.chromium.org/chromium/src/third_party/webrtc/voice_engine/voe_base_impl.cc?q=voe_base_impl.cc&dr&l=100).

Besides this, tests are updated, and some dead code is removed which
was found in the process.

Bug: webrtc:4690, webrtc:8591
Change-Id: I789d5296bf5efb7299a5ee05a4f3ce6abf9124b2
Reviewed-on: https://webrtc-review.googlesource.com/26681
Commit-Queue: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21301}
diff --git a/call/call_perf_tests.cc b/call/call_perf_tests.cc
index 90eaa5a..db3b5e4 100644
--- a/call/call_perf_tests.cc
+++ b/call/call_perf_tests.cc
@@ -158,10 +158,8 @@
   audio_net_config.queue_delay_ms = 500;
   audio_net_config.loss_percent = 5;
 
-  rtc::scoped_refptr<AudioProcessing> audio_processing;
   VoiceEngine* voice_engine;
   VoEBase* voe_base;
-  std::unique_ptr<FakeAudioDevice> fake_audio_device;
   VideoRtcpAndSyncObserver observer(Clock::GetRealTimeClock());
 
   std::map<uint8_t, MediaType> audio_pt_map;
@@ -177,14 +175,14 @@
 
   task_queue_.SendTask([&]() {
     metrics::Reset();
-    audio_processing = AudioProcessing::Create();
     voice_engine = VoiceEngine::Create();
     voe_base = VoEBase::GetInterface(voice_engine);
-    fake_audio_device = rtc::MakeUnique<FakeAudioDevice>(
-        FakeAudioDevice::CreatePulsedNoiseCapturer(256, 48000),
-        FakeAudioDevice::CreateDiscardRenderer(48000), audio_rtp_speed);
+    rtc::scoped_refptr<FakeAudioDevice> fake_audio_device =
+        new rtc::RefCountedObject<FakeAudioDevice>(
+            FakeAudioDevice::CreatePulsedNoiseCapturer(256, 48000),
+            FakeAudioDevice::CreateDiscardRenderer(48000), audio_rtp_speed);
     EXPECT_EQ(0, fake_audio_device->Init());
-    EXPECT_EQ(0, voe_base->Init(fake_audio_device.get(), audio_processing.get(),
+    EXPECT_EQ(0, voe_base->Init(fake_audio_device.get(), nullptr,
                                 decoder_factory_));
     VoEBase::ChannelConfig config;
     config.enable_voice_pacing = true;
@@ -194,7 +192,8 @@
     AudioState::Config send_audio_state_config;
     send_audio_state_config.voice_engine = voice_engine;
     send_audio_state_config.audio_mixer = AudioMixerImpl::Create();
-    send_audio_state_config.audio_processing = audio_processing;
+    send_audio_state_config.audio_processing = AudioProcessing::Create();
+    send_audio_state_config.audio_device_module = fake_audio_device;
     Call::Config sender_config(event_log_.get());
 
     auto audio_state = AudioState::Create(send_audio_state_config);
@@ -311,8 +310,6 @@
     DestroyCalls();
 
     VoiceEngine::Delete(voice_engine);
-
-    fake_audio_device.reset();
   });
 
   observer.PrintResults();