Remove "use_skia" variable from gyp.

skia/skia.gyp

Index: skia/skia.gyp
diff --git a/skia/skia.gyp b/skia/skia.gyp
index 25449bab2d027fe44d99f298cc7311d78ed15b92..e6555b64348c18ad74f568784c0379d1f344aaf3 100644
--- a/skia/skia.gyp
+++ b/skia/skia.gyp
@@ -475,6 +475,8 @@
         [ 'OS == "mac"', {
           'defines': [
             'SK_BUILD_FOR_MAC',
+            'SK_USE_MAC_CORE_TEXT',
+#           'SK_USE_COLOR_LUMINANCE',
           ],
           'include_dirs': [
             '../third_party/skia/include/utils/mac',
@@ -492,20 +494,6 @@
             # so no need for these generic versions.
             '../third_party/skia/src/ports/SkFontHost_tables.cpp',
           ],
-          'conditions': [
-             [ 'use_skia == 0', {
-               'sources/': [
-                 ['exclude', '/pdf/'],
-                 ['exclude', 'ext/vector_platform_device_skia\\.(cc|h)'],
-               ],
-            },
-            { # use_skia
-              'defines': [
-                'SK_USE_MAC_CORE_TEXT',
-#                'SK_USE_COLOR_LUMINANCE',
-              ],
-            }],
-          ],
         }],
         [ 'OS == "win"', {
           'sources!': [