Remove GraphicsContextCG.

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 439 matching lines @@
       'geometry/cg/FloatSizeCG.cpp',
       'geometry/cg/IntPointCG.cpp',
       'geometry/cg/IntRectCG.cpp',
       'geometry/cg/IntSizeCG.cpp',
       'geometry/mac/FloatPointMac.mm',
       'geometry/mac/FloatRectMac.mm',
       'geometry/mac/FloatSizeMac.mm',
       'geometry/mac/IntPointMac.mm',
       'geometry/mac/IntRectMac.mm',
       'geometry/mac/IntSizeMac.mm',
-      'graphics/cg/GraphicsContextCG.h',
       'graphics/cpu/arm/WebGLImageConversionNEON.h',
       'graphics/cpu/arm/filters/FEBlendNEON.h',
       'graphics/cpu/arm/filters/FECompositeArithmeticNEON.h',
       'graphics/cpu/arm/filters/FEGaussianBlurNEON.h',
       'graphics/cpu/arm/filters/FELightingNEON.h',
       'graphics/cpu/arm/filters/NEONHelpers.h',
       'graphics/filters/FEBlend.cpp',
       'graphics/filters/FEBlend.h',
       'graphics/filters/FEColorMatrix.cpp',
       'graphics/filters/FEColorMatrix.h',
@@ skipping 463 matching lines @@
       'graphics/ImageLayerChromiumTest.cpp',
       'graphics/OpaqueRectTrackingContentLayerDelegateTest.cpp',
       'graphics/test/MockImageDecoder.h',
       'graphics/test/MockWebGraphicsContext3D.h',
       'image-decoders/gif/GIFImageDecoderTest.cpp',
       'image-decoders/jpeg/JPEGImageDecoderTest.cpp',
       'image-decoders/webp/WEBPImageDecoderTest.cpp',
     ],
   },
 }