Move painting code from RenderFieldset to FieldsetPainter.

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 1432 matching lines @@
             'paint/BackgroundImageGeometry.cpp',
             'paint/BackgroundImageGeometry.h',
             'paint/ClipRecorder.cpp',
             'paint/ClipRecorder.h',
             'paint/DetailsMarkerPainter.cpp',
             'paint/DetailsMarkerPainter.h',
             'paint/DrawingRecorder.cpp',
             'paint/DrawingRecorder.h',
             'paint/EllipsisBoxPainter.cpp',
             'paint/EllipsisBoxPainter.h',
+            'paint/FieldsetPainter.h',
+            'paint/FieldsetPainter.cpp',
             'paint/FileUploadControlPainter.cpp',
             'paint/FileUploadControlPainter.h',
             'paint/FilterPainter.cpp',
             'paint/FilterPainter.h',
             'paint/FramePainter.cpp',
             'paint/FramePainter.h',
             'paint/GridPainter.cpp',
             'paint/GridPainter.h',
             'paint/HTMLCanvasPainter.cpp',
             'paint/HTMLCanvasPainter.h',
@@ skipping 2098 matching lines @@
             'rendering/style/OutlineValueTest.cpp',
             'rendering/style/RenderStyleTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }