SkAtomic: always use std::atomic

gyp/tools.gyp

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
     # GYP file to build various tools.
 #
 # To build on Linux:
 #  ./gyp_skia tools.gyp && make tools
 #
 {
@@ skipping 577 matching lines @@
           '<(skia_include_path)/pathops',
           '<(skia_include_path)/pipe',
           '<(skia_include_path)/ports',
           '<(skia_include_path)/svg/parser',
           '<(skia_include_path)/utils',
           '<(skia_include_path)/views',
           '<(skia_include_path)/xml',
         ],
         'paths_to_ignore': [
           '<(skia_include_path)/gpu/gl/GrGLConfig_chrome.h',
-          '<(skia_include_path)/ports/SkAtomics_std.h',
-          '<(skia_include_path)/ports/SkAtomics_atomic.h',
-          '<(skia_include_path)/ports/SkAtomics_sync.h',
           '<(skia_include_path)/ports/SkFontMgr_fontconfig.h',
           '<(skia_include_path)/ports/SkTypeface_mac.h',
           '<(skia_include_path)/ports/SkTypeface_win.h',
           '<(skia_include_path)/utils/ios',
           '<(skia_include_path)/utils/mac',
           '<(skia_include_path)/utils/win',
           '<(skia_include_path)/utils/SkDebugUtils.h',
           '<(skia_include_path)/utils/SkJSONCPP.h',
           '<(skia_include_path)/views/animated',
           '<(skia_include_path)/views/SkOSWindow_Android.h',
@@ skipping 117 matching lines @@
               'flags.gyp:flags',
               'skia_lib.gyp:skia_lib',
               'resources',
             ],
           },
         ],
       },
     ],
   ],
 }