remove more CriticalSectionWrappers.

webrtc/voice_engine/file_recorder.cc

Index: webrtc/voice_engine/file_recorder.cc
diff --git a/webrtc/voice_engine/file_recorder.cc b/webrtc/voice_engine/file_recorder.cc
index 9a0edb057ba29bb3006b9a837fa7df7bfbc164e5..9e1d5397bdf0cddb0b71865be78ff0e986aaf7a7 100644
--- a/webrtc/voice_engine/file_recorder.cc
+++ b/webrtc/voice_engine/file_recorder.cc
@@ -32,8 +32,6 @@ enum { MAX_AUDIO_BUFFER_IN_SAMPLES = 60 * 32 };
 enum { MAX_AUDIO_BUFFER_IN_BYTES = MAX_AUDIO_BUFFER_IN_SAMPLES * 2 };
 enum { kMaxAudioBufferQueueLength = 100 };
 
-class CriticalSectionWrapper;
-
 class FileRecorderImpl : public FileRecorder {
  public:
   FileRecorderImpl(uint32_t instanceID, FileFormats fileFormat);