GYP->GN of audio_device_tests. Remove dead code. Fix new warnings.

webrtc/modules/audio_device/include/fake_audio_device.h

Index: webrtc/modules/audio_device/include/fake_audio_device.h
diff --git a/webrtc/modules/audio_device/include/fake_audio_device.h b/webrtc/modules/audio_device/include/fake_audio_device.h
index 45bf45c18126696a1e79646473069cb0f71220ee..896ff9e430af1d4e048b4a7b7b5e3a2d21f2f87d 100644
--- a/webrtc/modules/audio_device/include/fake_audio_device.h
+++ b/webrtc/modules/audio_device/include/fake_audio_device.h
@@ -8,6 +8,9 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#ifndef WEBRTC_MODULES_AUDIO_DEVICE_INCLUDE_FAKE_AUDIO_DEVICE_H_
+#define WEBRTC_MODULES_AUDIO_DEVICE_INCLUDE_FAKE_AUDIO_DEVICE_H_
+
 #include "webrtc/modules/audio_device/include/audio_device.h"
 
 namespace webrtc {
@@ -146,7 +149,6 @@ class FakeAudioDeviceModule : public AudioDeviceModule {
   virtual int32_t GetLoudspeakerStatus(bool* enabled) const { return 0; }
   virtual bool BuiltInAECIsAvailable() const { return false; }
   virtual int32_t EnableBuiltInAEC(bool enable) { return -1; }
-  virtual bool BuiltInAECIsEnabled() const { return false; }
   virtual bool BuiltInAGCIsAvailable() const { return false; }
   virtual int32_t EnableBuiltInAGC(bool enable) { return -1; }
   virtual bool BuiltInNSIsAvailable() const { return false; }
@@ -154,3 +156,5 @@ class FakeAudioDeviceModule : public AudioDeviceModule {
 };
 
 }  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_DEVICE_INCLUDE_FAKE_AUDIO_DEVICE_H_