Fix presubmit errors caused by updated depot tools

src/platform-macos.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 540 matching lines @@
 }
 
 
 void Thread::YieldCPU() {
   sched_yield();
 }
 
 
 class MacOSMutex : public Mutex {
  public:
-
   MacOSMutex() {
     pthread_mutexattr_t attr;
     pthread_mutexattr_init(&attr);
     pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
     pthread_mutex_init(&mutex_, &attr);
   }
 
   virtual ~MacOSMutex() { pthread_mutex_destroy(&mutex_); }
 
   virtual int Lock() { return pthread_mutex_lock(&mutex_); }
@@ skipping 226 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SamplerThread::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal