Remove mutable from rtc::CriticalSections.

webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h

Index: webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h
diff --git a/webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h b/webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h
index 843be848e6a3db08cbf6b045b015db9b8f1ec788..46b7abf0970fcc3b7229dc4059cfc5b6d398cef1 100644
--- a/webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h
+++ b/webrtc/voice_engine/test/auto_test/fixtures/after_initialization_fixture.h
@@ -142,7 +142,7 @@ class LoopBackTransport : public webrtc::Transport {
     return true;
   }
 
-  mutable rtc::CriticalSection crit_;
+  rtc::CriticalSection crit_;
   const rtc::scoped_ptr<webrtc::EventWrapper> packet_event_;
   rtc::PlatformThread thread_;
   std::deque<Packet> packet_queue_ GUARDED_BY(crit_);