[S.P.] Move svg mask painting to SVGMaskPainter

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/Animation.idl',
             'animation/AnimationEffect.idl',
             'animation/AnimationNode.idl',
@@ skipping 1870 matching lines @@
             'paint/SVGContainerPainter.cpp',
             'paint/SVGContainerPainter.h',
             'paint/SVGForeignObjectPainter.cpp',
             'paint/SVGForeignObjectPainter.h',
             'paint/SVGImagePainter.cpp',
             'paint/SVGImagePainter.h',
             'paint/SVGInlineFlowBoxPainter.cpp',
             'paint/SVGInlineFlowBoxPainter.h',
             'paint/SVGInlineTextBoxPainter.cpp',
             'paint/SVGInlineTextBoxPainter.h',
+            'paint/SVGMaskPainter.cpp',
+            'paint/SVGMaskPainter.h',
             'paint/SVGPaintContext.cpp',
             'paint/SVGPaintContext.h',
             'paint/SVGRootInlineBoxPainter.cpp',
             'paint/SVGRootInlineBoxPainter.h',
             'paint/SVGRootPainter.cpp',
             'paint/SVGRootPainter.h',
             'paint/SVGShapePainter.cpp',
             'paint/SVGShapePainter.h',
             'paint/SVGTextPainter.cpp',
             'paint/SVGTextPainter.h',
@@ skipping 1921 matching lines @@
             'paint/ViewDisplayListTest.cpp',
             'streams/ExclusiveStreamReaderTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }