SkAtomic: always use std::atomic

gyp/ports.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.
 # Port-specific Skia library code.
 {
   'targets': [
     {
       'target_name': 'ports',
       'product_name': 'skia_ports',
@@ skipping 42 matching lines @@
         '../src/ports/SkOSFile_win.cpp',
         '../src/ports/SkOSLibrary.h',
         '../src/ports/SkOSLibrary_posix.cpp',
         '../src/ports/SkOSLibrary_win.cpp',
         '../src/ports/SkDiscardableMemory_none.cpp',
         '../src/ports/SkTime_Unix.cpp',
         '../src/ports/SkTime_win.cpp',
         '../src/ports/SkTLS_pthread.cpp',
         '../src/ports/SkTLS_win.cpp',
 
-        '../include/ports/SkAtomics_atomic.h',
-        '../include/ports/SkAtomics_std.h',
-        '../include/ports/SkAtomics_sync.h',
         '../include/ports/SkFontConfigInterface.h',
         '../include/ports/SkFontMgr.h',
         '../include/ports/SkFontMgr_android.h',
         '../include/ports/SkFontMgr_custom.h',
         '../include/ports/SkFontMgr_fontconfig.h',
         '../include/ports/SkFontMgr_indirect.h',
         '../include/ports/SkRemotableFontMgr.h',
       ],
       'sources/': [
         ['exclude', 'SkFontMgr_.+_factory\\.cpp$'],
@@ skipping 136 matching lines @@
         }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/ports',
         ],
       },
     },
   ],
 }