Move ThreadWrapper to ProcessThread in base.

webrtc/modules/audio_device/mac/audio_device_mac.h

Index: webrtc/modules/audio_device/mac/audio_device_mac.h
diff --git a/webrtc/modules/audio_device/mac/audio_device_mac.h b/webrtc/modules/audio_device/mac/audio_device_mac.h
index f2b66b4d061e5bfc475410103385258eaa267604..d908fc5752c170f37c7f523a082eb5017e9c2ba8 100644
--- a/webrtc/modules/audio_device/mac/audio_device_mac.h
+++ b/webrtc/modules/audio_device/mac/audio_device_mac.h
@@ -26,7 +26,7 @@ struct PaUtilRingBuffer;
 namespace webrtc
 {
 class EventWrapper;
-class ThreadWrapper;
+class PlatformThread;
 
 const uint32_t N_REC_SAMPLES_PER_SEC = 48000;
 const uint32_t N_PLAY_SAMPLES_PER_SEC = 48000;
@@ -283,10 +283,10 @@ private:
     EventWrapper& _stopEvent;
 
     // Only valid/running between calls to StartRecording and StopRecording.
-    rtc::scoped_ptr<ThreadWrapper> capture_worker_thread_;
+    rtc::scoped_ptr<PlatformThread> capture_worker_thread_;
 
     // Only valid/running between calls to StartPlayout and StopPlayout.
-    rtc::scoped_ptr<ThreadWrapper> render_worker_thread_;
+    rtc::scoped_ptr<PlatformThread> render_worker_thread_;
 
     int32_t _id;