Create rtc::AtomicInt POD struct.

webrtc/system_wrappers/include/trace.h

 /*
  *  Copyright (c) 2012 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.
  *
  *  System independent wrapper for logging runtime information to file.
  *  Note: All log messages will be written to the same trace file.
  *  Note: If too many messages are written to file there will be a build up of
  *  messages. Apply filtering to avoid that.
  */
 
 #ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_TRACE_H_
 #define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_TRACE_H_
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/common_types.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 #if defined(WEBRTC_RESTRICT_LOGGING)
 // Disable all TRACE macros. The LOG macro is still functional.
 #define WEBRTC_TRACE true ? (void) 0 : Trace::Add
 #else
 #define WEBRTC_TRACE Trace::Add
@@ skipping 48 matching lines @@
   // id is an identifier that should be unique for that set of classes that
   // are associated (e.g. all instances owned by an engine).
   // msg and the ellipsis are the same as e.g. sprintf.
   // TODO(hellner) Why is TraceModule not defined in this file?
   static void Add(const TraceLevel level,
                   const TraceModule module,
                   const int32_t id,
                   const char* msg, ...);
 
  private:
-  static volatile int level_filter_;
+  static rtc::AtomicInt level_filter_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_TRACE_H_