remove SK_SUPPORT_LEGACY_BLURMASKFILTER_STYLE -- not needed

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 321 matching lines @@
         'IGNORE_ROT_AA_RECT_OPT',
         # Disable this check because it is too strict for some chromium-specific
         # subclasses of SkPixelRef. See bug: crbug.com/171776.
         'SK_DISABLE_PIXELREF_LOCKCOUNT_BALANCE_CHECK',
         'SkLONGLONG int64_t',
         'SK_DEFAULT_FONT_CACHE_LIMIT   (768 * 1024)',
         'SK_ATOMICS_PLATFORM_H "../../src/ports/SkAtomics_sync.h"',
         'SK_MUTEX_PLATFORM_H "../../src/ports/SkMutex_pthread.h"',
         # Still need to switch Android to the new name for N32.
         'kNative_8888_SkColorType kN32_SkColorType',
-        'SK_SUPPORT_LEGACY_BLURMASKFILTER_STYLE',
         # Needed until we fix skbug.com/2440.
         'SK_SUPPORT_LEGACY_CLIPTOLAYERFLAG',
         # Transitional, for deprecated SkCanvas::SaveFlags methods.
         'SK_ATTR_DEPRECATED=SK_NOTHING_ARG1',
         'SK_SUPPORT_LEGACY_SHADER_LOCALMATRIX',
         'SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE (512 * 1024)',
         'SK_IGNORE_ETC1_SUPPORT',
         # Defines from skia_for_android_framework_defines.gypi
         '<@(skia_for_android_framework_defines)',
       ],
@@ skipping 331 matching lines @@
         'SK_BUILD_JSON_WRITER',
       ]
     }],
 
   ], # end 'conditions'
   # The Xcode SYMROOT must be at the root. See build/common.gypi in chromium for more details
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }