Move SystemInfo to rtc_base_approved and delete unused code.

webrtc/system_wrappers/source/cpu_info.cc

 /*
  *  Copyright (c) 2011 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.
  */
 
 #include "webrtc/system_wrappers/interface/cpu_info.h"
 
-#if defined(_WIN32)
-#include <Windows.h>
-#elif defined(WEBRTC_MAC)
-#include <sys/sysctl.h>
-#include <sys/types.h>
-#else // defined(WEBRTC_LINUX) or defined(WEBRTC_ANDROID)
-#include <unistd.h>
-#endif
-
-#include "webrtc/system_wrappers/interface/trace.h"
+#include "webrtc/base/systeminfo.h"
 
 namespace webrtc {
 
-uint32_t CpuInfo::number_of_cores_ = 0;
-
 uint32_t CpuInfo::DetectNumberOfCores() {
-  if (!number_of_cores_) {
-#if defined(_WIN32)
-    SYSTEM_INFO si;
-    GetSystemInfo(&si);
-    number_of_cores_ = static_cast<uint32_t>(si.dwNumberOfProcessors);
-    WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
-                 "Available number of cores:%d", number_of_cores_);
-
-#elif defined(WEBRTC_LINUX) || defined(WEBRTC_ANDROID)
-    number_of_cores_ = static_cast<uint32_t>(sysconf(_SC_NPROCESSORS_ONLN));
-    WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
-                 "Available number of cores:%d", number_of_cores_);
-
-#elif defined(WEBRTC_MAC)
-    int name[] = {CTL_HW, HW_AVAILCPU};
-    int ncpu;
-    size_t size = sizeof(ncpu);
-    if (0 == sysctl(name, 2, &ncpu, &size, NULL, 0)) {
-      number_of_cores_ = static_cast<uint32_t>(ncpu);
-      WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
-                   "Available number of cores:%d", number_of_cores_);
-    } else {
-      WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
-                   "Failed to get number of cores");
-      number_of_cores_ = 1;
-    }
-#else
-    WEBRTC_TRACE(kTraceWarning, kTraceUtility, -1,
-                 "No function to get number of cores");
-    number_of_cores_ = 1;
-#endif
-  }
-  return number_of_cores_;
+  return static_cast<uint32_t>(rtc::SystemInfo::GetMaxCpus());
 }
 
 }  // namespace webrtc