Switch usage of _DEBUG macro to NDEBUG.

webrtc/base/taskparent.h

 /*
  *  Copyright 2004 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 14 matching lines @@
  public:
   TaskParent(Task *derived_instance, TaskParent *parent);
   explicit TaskParent(TaskRunner *derived_instance);
   virtual ~TaskParent();
 
   TaskParent *GetParent() { return parent_; }
   TaskRunner *GetRunner() { return runner_; }
 
   bool AllChildrenDone();
   bool AnyChildError();
-#ifdef _DEBUG
+#if !defined(NDEBUG)
   bool IsChildTask(Task *task);
 #endif
 
  protected:
   void OnStopped(Task *task);
   void AbortAllChildren();
   TaskParent *parent() {
     return parent_;
   }
 
  private:
   void Initialize();
   void OnChildStopped(Task *child);
   void AddChild(Task *child);
 
   TaskParent *parent_;
   TaskRunner *runner_;
   bool child_error_;
   typedef std::set<Task *> ChildSet;
   scoped_ptr<ChildSet> children_;
   RTC_DISALLOW_COPY_AND_ASSIGN(TaskParent);
 };
 
 
 } // namespace rtc
 
 #endif  // WEBRTC_BASE_TASKPARENT_H__