Revert of Revert "Remove CpuMonitor and related, unused, code."

webrtc/base/BUILD.gn

 # Copyright (c) 2014 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.
 
 import("//build/config/crypto.gni")
 import("//build/config/ui.gni")
@@ skipping 198 matching lines @@
     "asynctcpsocket.h",
     "asyncudpsocket.cc",
     "asyncudpsocket.h",
     "autodetectproxy.cc",
     "autodetectproxy.h",
     "base64.cc",
     "base64.h",
     "basicdefs.h",
     "common.cc",
     "common.h",
-    "cpumonitor.cc",
-    "cpumonitor.h",
     "crc32.cc",
     "crc32.h",
     "cryptstring.cc",
     "cryptstring.h",
     "diskcache.cc",
     "diskcache.h",
     "filerotatingstream.cc",
     "filerotatingstream.h",
     "fileutils.cc",
     "fileutils.h",
@@ skipping 398 matching lines @@
     defines += [ "CARBON_DEPRECATED=YES" ]
   }
 
   if (is_linux || is_android) {
     sources += [
       "linux.cc",
       "linux.h",
     ]
   }
 }