Replace GR_MAC_BUILD by SK_BUILD_FOR_MAC.

gyp/gpu.gyp

Index: gyp/gpu.gyp
diff --git a/gyp/gpu.gyp b/gyp/gpu.gyp
index 7e74bade48c73246ec660b3b46e055028e838a62..cb39c59aeb988c8d0c67bf40dd441cea9e043dfd 100644
--- a/gyp/gpu.gyp
+++ b/gyp/gpu.gyp
@@ -25,31 +25,6 @@
         'sources/': [ ['exclude', '_nacl.(h|cpp)$'],
         ],
       }],
-      [ 'skia_os == "android"', {
-        'defines': [
-          'GR_ANDROID_BUILD=1',
-        ],
-      }],
-      [ 'skia_os == "mac"', {
-        'defines': [
-          'GR_MAC_BUILD=1',
-        ],
-      }],
-      [ 'skia_os == "linux" or skia_os == "chromeos"', {
-        'defines': [
-          'GR_LINUX_BUILD=1',
-        ],
-      }],
-      [ 'skia_os == "ios"', {
-        'defines': [
-          'GR_IOS_BUILD=1',
-        ],
-      }],
-      [ 'skia_os == "win"', {
-        'defines': [
-          'GR_WIN32_BUILD=1',
-        ],
-      }],
       # nullify the targets in this gyp file if skia_gpu is 0
       [ 'skia_gpu == 0', {
         'sources/': [
@@ -83,29 +58,8 @@
     ],
     'direct_dependent_settings': {
       'conditions': [
-        [ 'skia_os == "android"', {
-          'defines': [
-            'GR_ANDROID_BUILD=1',
-          ],
-        }],
-        [ 'skia_os == "mac"', {
-          'defines': [
-            'GR_MAC_BUILD=1',
-          ],
-        }],
-        [ 'skia_os == "linux"', {
-          'defines': [
-            'GR_LINUX_BUILD=1',
-          ],
-        }],
-        [ 'skia_os == "ios"', {
-          'defines': [
-            'GR_IOS_BUILD=1',
-          ],
-        }],
         [ 'skia_os == "win"', {
           'defines': [
-            'GR_WIN32_BUILD=1',
             'GR_GL_FUNCTION_TYPE=__stdcall',
           ],
         }],