[Mac] In PlatformThread::CurrentId(), use pthread_self() instead of mach_thread_self().

base/threading/platform_thread.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // WARNING: You should *NOT* be using this class directly.  PlatformThread is
 // the low-level platform-specific abstraction to the OS's threading interface.
 // You should instead be using a message-loop driven Thread, see thread.h.
 
 #ifndef BASE_THREADING_PLATFORM_THREAD_H_
 #define BASE_THREADING_PLATFORM_THREAD_H_
 #pragma once
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/time.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #elif defined(OS_POSIX)
 #include <pthread.h>
-#if defined(OS_MACOSX)
-#include <mach/mach.h>
-#else  // OS_POSIX && !OS_MACOSX
 #include <unistd.h>
 #endif
-#endif
 
 namespace base {
 
 // PlatformThreadHandle should not be assumed to be a numeric type, since the
 // standard intends to allow pthread_t to be a structure.  This means you
 // should not initialize it to a value, like 0.  If it's a member variable, the
 // constructor can safely "value initialize" using () in the initializer list.
 #if defined(OS_WIN)
 typedef DWORD PlatformThreadId;
 typedef void* PlatformThreadHandle;  // HANDLE
 const PlatformThreadHandle kNullThreadHandle = NULL;
 #elif defined(OS_POSIX)
 typedef pthread_t PlatformThreadHandle;
 const PlatformThreadHandle kNullThreadHandle = 0;
-#if defined(OS_MACOSX)
-typedef mach_port_t PlatformThreadId;
-#else  // OS_POSIX && !OS_MACOSX
 typedef pid_t PlatformThreadId;
 #endif
-#endif
 
 const PlatformThreadId kInvalidThreadId = 0;
 
 // Valid values for SetThreadPriority()
 enum ThreadPriority{
   kThreadPriority_Normal,
   // Suitable for low-latency, glitch-resistant audio.
   kThreadPriority_RealtimeAudio
 };
 
@@ skipping 52 matching lines @@
   static void SetThreadPriority(PlatformThreadHandle handle,
                                 ThreadPriority priority);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformThread);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_PLATFORM_THREAD_H_