Added A/V sync tests with drifting clocks.

webrtc/test/fake_audio_device.h

Index: webrtc/test/fake_audio_device.h
diff --git a/webrtc/test/fake_audio_device.h b/webrtc/test/fake_audio_device.h
index ce480c1554dac7038d1b3c6cedb57dd1b9649732..a99578ad2437e23097f98d82a6cbd77b2c8e0b63 100644
--- a/webrtc/test/fake_audio_device.h
+++ b/webrtc/test/fake_audio_device.h
@@ -16,6 +16,7 @@
 #include "webrtc/base/platform_thread.h"
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/modules/audio_device/include/fake_audio_device.h"
+#include "webrtc/test/drifting_clock.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
@@ -29,7 +30,7 @@ namespace test {
 
 class FakeAudioDevice : public FakeAudioDeviceModule {
  public:
-  FakeAudioDevice(Clock* clock, const std::string& filename);
+  FakeAudioDevice(Clock* clock, const std::string& filename, float drift);
 
   virtual ~FakeAudioDevice();
 
@@ -54,8 +55,10 @@ class FakeAudioDevice : public FakeAudioDeviceModule {
   bool capturing_;
   int8_t captured_audio_[kBufferSizeBytes];
   int8_t playout_buffer_[kBufferSizeBytes];
+  float drift_ = .0;
   int64_t last_playout_ms_;
 
+  DriftingClock drifting_clock_;
   Clock* clock_;
   rtc::scoped_ptr<EventTimerWrapper> tick_;
   rtc::CriticalSection lock_;