remove legacy moz flags

gyp/common_conditions.gypi

 # conditions used in both common.gypi and skia.gyp in chromium
 #
 {
   'defines': [
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=<(skia_static_initializers)',
     'SK_SUPPORT_GPU=<(skia_gpu)',
     'SK_SUPPORT_OPENCL=<(skia_opencl)',
     'SK_FORCE_DISTANCEFIELD_FONTS=<(skia_force_distancefield_fonts)',
   ],
   'conditions' : [
@@ skipping 656 matching lines @@
     # We can POD-style initialization of static mutexes to avoid generating
     # static initializers if we're using a pthread-compatible thread interface.
     [ 'skia_os != "win"', {
       'defines': [
         'SK_USE_POSIX_THREADS',
       ],
     }],
 
     [ 'skia_moz2d', {
       'defines': [
-        'SK_SUPPORT_LEGACY_LAYERRASTERIZER_API=1',
-        'SK_SUPPORT_LEGACY_COMPATIBLEDEVICE_CONFIG=1',
-        'SK_SUPPORT_LEGACY_GETTOTALCLIP=1',
+        # add flags here (e.g. SK_SUPPORT_LEGACY_...) needed by moz2d
       ],
     }],
 
   ], # end 'conditions'
   # The Xcode SYMROOT must be at the root. See build/common.gypi in chromium for more details
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }