Move NumberOfProcessorsOnline from CPU to OS

src/cpu.cc

 // Copyright 2013 the V8 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.
 
 #include "cpu.h"
 
 #if V8_LIBC_MSVCRT
 #include <intrin.h>  // __cpuid()
 #endif
 #if V8_OS_POSIX
@@ skipping 478 matching lines @@
     part_ = strtol(part, &end, 0);
     if (end == part) {
       part_ = 0;
     }
     delete[] part;
   }
 
 #endif
 }
 
-
-// static
-int CPU::NumberOfProcessorsOnline() {
-#if V8_OS_WIN
-  SYSTEM_INFO info;
-  GetSystemInfo(&info);
-  return info.dwNumberOfProcessors;
-#else
-  return static_cast<int>(sysconf(_SC_NPROCESSORS_ONLN));
-#endif
-}
-
 } }  // namespace v8::internal