Move NinePieceImage painting to a separate class

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1883 matching lines @@
             'paint/LineBoxListPainter.cpp',
             'paint/LineBoxListPainter.h',
             'paint/ListItemPainter.cpp',
             'paint/ListItemPainter.h',
             'paint/ListMarkerPainter.cpp',
             'paint/ListMarkerPainter.h',
             'paint/MediaControlsPainter.cpp',
             'paint/MediaControlsPainter.h',
             'paint/MultiColumnSetPainter.cpp',
             'paint/MultiColumnSetPainter.h',
+            'paint/NinePieceImagePainter.cpp',
+            'paint/NinePieceImagePainter.h',
             'paint/ObjectPainter.cpp',
             'paint/ObjectPainter.h',
             'paint/PaintInfo.h',
             'paint/PaintPhase.cpp',
             'paint/PaintPhase.h',
             'paint/PartPainter.cpp',
             'paint/PartPainter.h',
             'paint/ReplacedPainter.cpp',
             'paint/ReplacedPainter.h',
             'paint/ReplicaPainter.cpp',
@@ skipping 2002 matching lines @@
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }