Merge FontPlatformDataSkia with FontPlatformData

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 389 matching lines @@
       'fonts/mac/MemoryActivatedFont.mm',
       'fonts/opentype/OpenTypeSanitizer.cpp',
       'fonts/opentype/OpenTypeSanitizer.h',
       'fonts/opentype/OpenTypeTypes.h',
       'fonts/opentype/OpenTypeUtilities.cpp',
       'fonts/opentype/OpenTypeUtilities.h',
       'fonts/opentype/OpenTypeVerticalData.cpp',
       'fonts/opentype/OpenTypeVerticalData.h',
       'fonts/skia/FontCacheSkia.cpp',
       'fonts/skia/FontCustomPlatformDataSkia.cpp',
-      'fonts/skia/FontPlatformDataSkia.cpp',
       'fonts/win/FontCacheSkiaWin.cpp',
       'fonts/win/FontFallbackWin.cpp',
       'fonts/win/FontFallbackWin.h',
       'fonts/win/FontPlatformDataWin.cpp',
       'geometry/DoublePoint.h',
       'geometry/DoubleSize.cpp',
       'geometry/DoubleSize.h',
       'geometry/FloatBoxExtent.h',
       'geometry/FloatPolygon.cpp',
       'geometry/FloatPolygon.h',
@@ skipping 540 matching lines @@
       'graphics/ImageFrameGeneratorTest.cpp',
       'graphics/ImageLayerChromiumTest.cpp',
       'graphics/test/MockImageDecoder.h',
       'graphics/test/MockWebGraphicsContext3D.h',
       'image-decoders/gif/GIFImageDecoderTest.cpp',
       'image-decoders/jpeg/JPEGImageDecoderTest.cpp',
       'image-decoders/webp/WEBPImageDecoderTest.cpp',
     ],
   },
 }