Use C++11 atomics

base/base.gypi

Index: base/base.gypi
diff --git a/base/base.gypi b/base/base.gypi
index 8a37249397cc03bce57aa0b2da263246bc66d1b9..cb39a050cd631115281d4a398671534d975e484b 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -79,12 +79,7 @@
           'atomic_ref_count.h',
           'atomic_sequence_num.h',
           'atomicops.h',
-          'atomicops_internals_gcc.h',
-          'atomicops_internals_mac.h',
-          'atomicops_internals_tsan.h',
-          'atomicops_internals_x86_gcc.cc',
-          'atomicops_internals_x86_gcc.h',
-          'atomicops_internals_x86_msvc.h',
+          'atomicops_internals_portable.h',
           'barrier_closure.cc',
           'barrier_closure.h',
           'base64.cc',
@@ -738,9 +733,6 @@
               'sources/': [
                 ['exclude', '^nix/'],
               ],
-              'sources!': [
-                'atomicops_internals_x86_gcc.cc',
-              ],
           }],
           ['<(use_glib)==0 or >(nacl_untrusted_build)==1', {
               'sources!': [
@@ -827,7 +819,6 @@
             ],
             'sources/': [
               # Pull in specific files for host builds.
-              ['include', '^atomicops_internals_x86_gcc\\.cc$'],
               ['include', '^threading/platform_thread_linux\\.cc$'],
             ],
           }],
@@ -842,7 +833,6 @@
             'sources/': [
               # Pull in specific Mac files for iOS (which have been filtered out
               # by file name rules).
-              ['include', '^atomicops_internals_mac\\.'],
               ['include', '^base_paths_mac\\.'],
               ['include', '^files/file_util_mac\\.'],
               ['include', '^file_version_info_mac\\.'],