In PeerConnectionTestWrapper, put audio input on a separate thread.

talk/app/webrtc/test/fakeaudiocapturemodule.cc

Index: talk/app/webrtc/test/fakeaudiocapturemodule.cc
diff --git a/talk/app/webrtc/test/fakeaudiocapturemodule.cc b/talk/app/webrtc/test/fakeaudiocapturemodule.cc
index 47f17a1739abe566a38bad9d14ebdfa24b0507d2..065ef25426c42f5c47018cee3f9292197f6d5e11 100644
--- a/talk/app/webrtc/test/fakeaudiocapturemodule.cc
+++ b/talk/app/webrtc/test/fakeaudiocapturemodule.cc
@@ -54,7 +54,6 @@ static const uint32_t kMaxVolume = 14392;
 enum {
   MSG_START_PROCESS,
   MSG_RUN_PROCESS,
-  MSG_STOP_PROCESS,
 };
 
 FakeAudioCaptureModule::FakeAudioCaptureModule(
@@ -74,7 +73,7 @@ FakeAudioCaptureModule::FakeAudioCaptureModule(
 
 FakeAudioCaptureModule::~FakeAudioCaptureModule() {
   // Ensure that thread stops calling ProcessFrame().
-  process_thread_->Send(this, MSG_STOP_PROCESS);
+  process_thread_->Clear(this);
 }
 
 rtc::scoped_refptr<FakeAudioCaptureModule> FakeAudioCaptureModule::Create(
@@ -601,9 +600,6 @@ void FakeAudioCaptureModule::OnMessage(rtc::Message* msg) {
     case MSG_RUN_PROCESS:
       ProcessFrameP();
       break;
-    case MSG_STOP_PROCESS:
-      StopProcessP();
-      break;
     default:
       // All existing messages should be caught. Getting here should never
       // happen.
@@ -652,7 +648,8 @@ void FakeAudioCaptureModule::UpdateProcessing(bool start) {
   if (start) {
     process_thread_->Post(this, MSG_START_PROCESS);
   } else {
-    process_thread_->Send(this, MSG_STOP_PROCESS);
+    process_thread_->Clear(this);
+    started_ = false;
   }
 }
 
@@ -747,8 +744,3 @@ void FakeAudioCaptureModule::SendFrameP() {
   SetMicrophoneVolume(current_mic_level);
 }
 
-void FakeAudioCaptureModule::StopProcessP() {
-  ASSERT(rtc::Thread::Current() == process_thread_);
-  started_ = false;
-  process_thread_->Clear(this);
-}