Revert of Switch to HarfBuzz on Mac and remove CoreText shaper

Source/build/features.gypi

Index: Source/build/features.gypi
diff --git a/Source/build/features.gypi b/Source/build/features.gypi
index 503af4f294fe40ef1d8eba74471dc1a29dbcefc7..237be2273d2257d40734c705171fa2bff04604db 100644
--- a/Source/build/features.gypi
+++ b/Source/build/features.gypi
@@ -33,7 +33,6 @@
   'variables': {
     'feature_defines': [
       'ENABLE_SVG_FONTS=1',
-      'ENABLE_OPENTYPE_VERTICAL=1',
       # WTF_USE_DYNAMIC_ANNOTATIONS=1 may be defined in build/common.gypi
       # We can't define it here because it should be present only
       # in Debug or release_valgrind_build=1 builds.
@@ -72,6 +71,12 @@
           'ENABLE_WEB_AUDIO=1',
         ],
       }],
+      # Mac OS X has not implemented support for ENABLE(OPENTYPE_VERTICAL) yet
+      ['OS!="mac"', {
+        'feature_defines': [
+          'ENABLE_OPENTYPE_VERTICAL=1',
+        ],
+      }],
       ['use_default_render_theme==1', {
         'feature_defines': [
           'WTF_USE_DEFAULT_RENDER_THEME=1',