Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/scoped_autorelease_pool.h

 /*
  *  Copyright 2008 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 25 matching lines @@
 class ScopedAutoreleasePool {
  public:
   ScopedAutoreleasePool();
   ~ScopedAutoreleasePool();
 
  private:
   // Declaring private overrides of new and delete here enforces the "only use
   // as a stack object" discipline.
   //
   // Note: new is declared as "throw()" to get around a gcc warning about new
-  // returning NULL, but this method will never get called and therefore will
+  // returning null, but this method will never get called and therefore will
   // never actually throw any exception.
-  void* operator new(size_t size) throw() { return NULL; }
+  void* operator new(size_t size) throw() { return nullptr; }
   void operator delete (void* ptr) {}
 
   NSAutoreleasePool* pool_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(ScopedAutoreleasePool);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_MAC
 #endif  // WEBRTC_BASE_SCOPED_AUTORELEASE_POOL_H__