Replace Atomic32 with webrtc/base/atomicops.h.

webrtc/system_wrappers/system_wrappers.gyp

Index: webrtc/system_wrappers/system_wrappers.gyp
diff --git a/webrtc/system_wrappers/system_wrappers.gyp b/webrtc/system_wrappers/system_wrappers.gyp
index 02e930575c8df425593154035f3ab7db200c1cb8..a96d0f52dbd2263602535fdb1f4f8aa356dc9bf6 100644
--- a/webrtc/system_wrappers/system_wrappers.gyp
+++ b/webrtc/system_wrappers/system_wrappers.gyp
@@ -19,7 +19,6 @@
       'sources': [
         'interface/aligned_array.h',
         'interface/aligned_malloc.h',
-        'interface/atomic32.h',
         'interface/clock.h',
         'interface/condition_variable_wrapper.h',
         'interface/cpu_info.h',
@@ -52,9 +51,6 @@
         'interface/trace_event.h',
         'interface/utf_util_win.h',
         'source/aligned_malloc.cc',
-        'source/atomic32_mac.cc',
-        'source/atomic32_posix.cc',
-        'source/atomic32_win.cc',
         'source/clock.cc',
         'source/condition_variable.cc',
         'source/condition_variable_posix.cc',
@@ -159,9 +155,6 @@
           'link_settings': {
             'libraries': [ '$(SDKROOT)/System/Library/Frameworks/ApplicationServices.framework', ],
           },
-          'sources!': [
-            'source/atomic32_posix.cc',
-          ],
         }],
         ['OS=="ios" or OS=="mac"', {
           'defines': [
@@ -175,20 +168,6 @@
           },
         }],
       ], # conditions
-      'target_conditions': [
-        # We need to do this in a target_conditions block to override the
-        # filename_rules filters.
-        ['OS=="ios"', {
-          # Pull in specific Mac files for iOS (which have been filtered out
-          # by file name rules).
-          'sources/': [
-            ['include', '^source/atomic32_mac\\.'],
-          ],
-          'sources!': [
-            'source/atomic32_posix.cc',
-          ],
-        }],
-      ],
       # Disable warnings to enable Win64 build, issue 1323.
       'msvs_disabled_warnings': [
         4267,  # size_t to int truncation.