Remove unused ConditionVariableWrapper on POSIX platforms

webrtc/system_wrappers/include/critical_section_wrapper.h

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 33 matching lines @@
   void Leave() UNLOCK_FUNCTION();
 
 private:
 #if defined (WEBRTC_WIN)
   CRITICAL_SECTION crit_;
 
   // TODO(tommi): Remove friendness.
   friend class ConditionVariableEventWin;
   friend class ConditionVariableNativeWin;
 #else
-  // TODO(tommi): Remove friendness.
   pthread_mutex_t mutex_;
-  friend class ConditionVariablePosix;
 #endif
 };
 
 // RAII extension of the critical section. Prevents Enter/Leave mismatches and
 // provides more compact critical section syntax.
 class SCOPED_LOCKABLE CriticalSectionScoped {
  public:
   explicit CriticalSectionScoped(CriticalSectionWrapper* critsec)
       EXCLUSIVE_LOCK_FUNCTION(critsec)
       : ptr_crit_sec_(critsec) {
     ptr_crit_sec_->Enter();
   }
 
   ~CriticalSectionScoped() UNLOCK_FUNCTION() { ptr_crit_sec_->Leave(); }
 
  private:
   CriticalSectionWrapper* ptr_crit_sec_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CRITICAL_SECTION_WRAPPER_H_