Remove mutable from rtc::CriticalSection members.

talk/app/webrtc/test/fakeaudiocapturemodule.h

Index: talk/app/webrtc/test/fakeaudiocapturemodule.h
diff --git a/talk/app/webrtc/test/fakeaudiocapturemodule.h b/talk/app/webrtc/test/fakeaudiocapturemodule.h
index 4284b9ed51b89778e33aa0f2893be4a98fff9603..fdac0b9ed252284f9c1b82f07aa2704c27b24135 100644
--- a/talk/app/webrtc/test/fakeaudiocapturemodule.h
+++ b/talk/app/webrtc/test/fakeaudiocapturemodule.h
@@ -278,7 +278,7 @@ class FakeAudioCaptureModule
 
   // Protects variables that are accessed from process_thread_ and
   // the main thread.
-  mutable rtc::CriticalSection crit_;
+  rtc::CriticalSection crit_;
   // Protects |audio_callback_| that is accessed from process_thread_ and
   // the main thread.
   rtc::CriticalSection crit_callback_;