Move IsRunningOnChromeOS to SysInfo

tools/gn/secondary/base/BUILD.gn

 # Copyright (c) 2013 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.
 
 config("base_libs") {
   if (!is_win) {
     ldflags = [ "-ldl" ]
   }
 }
 
@@ skipping 74 matching lines @@
     "bind_internal.h",
     "bind_internal_win.h",
     "bits.h",
     "build_time.cc",
     "build_time.h",
     "callback.h",
     "callback_helpers.h",
     "callback_internal.cc",
     "callback_internal.h",
     "cancelable_callback.h",
-    "chromeos/chromeos_version.cc",
-    "chromeos/chromeos_version.h",
     "command_line.cc",
     "command_line.h",
     "compiler_specific.h",
     "containers/hash_tables.h",
     "containers/linked_list.h",
     "containers/mru_cache.h",
     "containers/small_map.h",
     "containers/stack_container.h",
     "cpu.cc",
     "cpu.h",
@@ skipping 897 matching lines @@
 static_library("run_all_unittests") {
   external = true
   sources = [
     "test/run_all_unittests.cc",
   ]
   deps = [
     ":test_support_base",
   ]
 }