remove unused Kernel33MaskFilter

gyp/public_headers.gypi

 # Include this gypi to include all public header files that exist in the
 # include directory.
 #
 # The list is computed by running 'find include -name *.h' in the root dir of
 # the project.
 #
 {
   'variables': {
     'header_filenames': [
       'pdf/SkPDFDevice.h',
@@ skipping 65 matching lines @@
       'effects/SkArithmeticMode.h',
       'effects/SkMergeImageFilter.h',
       'effects/SkPerlinNoiseShader.h',
       'effects/SkLerpXfermode.h',
       'effects/SkLumaColorFilter.h',
       'effects/SkRectShaderImageFilter.h',
       'effects/SkMagnifierImageFilter.h',
       'effects/SkBicubicImageFilter.h',
       'effects/SkPorterDuff.h',
       'effects/SkBlurImageFilter.h',
-      'effects/SkKernel33MaskFilter.h',
       'effects/SkTableMaskFilter.h',
       'effects/SkAvoidXfermode.h',
       'effects/SkBitmapSource.h',
       'effects/SkCornerPathEffect.h',
       'effects/SkTransparentShader.h',
       'effects/SkStippleMaskFilter.h',
       'effects/SkPaintFlagsDrawFilter.h',
       'effects/SkOffsetImageFilter.h',
       'effects/SkDiscretePathEffect.h',
       'effects/SkTableColorFilter.h',
@@ skipping 192 matching lines @@
       'views/unix/XkeysToSkKeys.h',
       'views/SkKey.h',
       'views/SkView.h',
       'views/SkOSMenu.h',
       'views/SkOSWindow_Unix.h',
       'views/SkWidget.h',
       'views/SkOSWindow_Win.h',
     ],
   },
 }