Optimize CSS box-shadow performance

gyp/core.gypi

 # Include this gypi to include all 'core' files
 # The parent gyp/gypi file must define
 #       'skia_src_path'     e.g. skia/trunk/src
 #       'skia_include_path' e.g. skia/trunk/include
 #
 # The skia build defines these in common_variables.gypi
 #
 {
     'sources': [
         '<(skia_src_path)/core/SkAAClip.cpp',
@@ skipping 90 matching lines @@
         '<(skia_src_path)/core/SkGlyphCache_Globals.h',
         '<(skia_src_path)/core/SkGraphics.cpp',
         '<(skia_src_path)/core/SkInstCnt.cpp',
         '<(skia_src_path)/core/SkImageFilter.cpp',
         '<(skia_src_path)/core/SkImageInfo.cpp',
         '<(skia_src_path)/core/SkImageGenerator.cpp',
         '<(skia_src_path)/core/SkLocalMatrixShader.cpp',
         '<(skia_src_path)/core/SkLineClipper.cpp',
         '<(skia_src_path)/core/SkMallocPixelRef.cpp',
         '<(skia_src_path)/core/SkMask.cpp',
+        '<(skia_src_path)/core/SkMaskCache.cpp',
         '<(skia_src_path)/core/SkMaskFilter.cpp',
         '<(skia_src_path)/core/SkMaskGamma.cpp',
         '<(skia_src_path)/core/SkMaskGamma.h',
         '<(skia_src_path)/core/SkMath.cpp',
         '<(skia_src_path)/core/SkMatrix.cpp',
         '<(skia_src_path)/core/SkMessageBus.h',
         '<(skia_src_path)/core/SkMetaData.cpp',
         '<(skia_src_path)/core/SkMipMap.cpp',
         '<(skia_src_path)/core/SkMultiPictureDraw.cpp',
         '<(skia_src_path)/core/SkPackBits.cpp',
@@ skipping 255 matching lines @@
         '<(skia_src_path)/pathops/SkPathOpsPoint.h',
         '<(skia_src_path)/pathops/SkPathOpsQuad.h',
         '<(skia_src_path)/pathops/SkPathOpsRect.h',
         '<(skia_src_path)/pathops/SkPathOpsTriangle.h',
         '<(skia_src_path)/pathops/SkPathOpsTypes.h',
         '<(skia_src_path)/pathops/SkPathWriter.h',
         '<(skia_src_path)/pathops/SkQuarticRoot.h',
         '<(skia_src_path)/pathops/SkReduceOrder.h',
     ],
 }