Add an intermediate function to generate 2 paint-order lists.

Source/WebCore/WebCore.gypi

 {
     'variables': {
         'project_dir': ['.'],
         'webcore_include_dirs': [
           '.',
           '..',
           'Modules/battery',
           'Modules/filesystem',
           'Modules/gamepad',
           'Modules/geolocation',
@@ skipping 311 matching lines @@
             'dom/MutationRecord.idl',
             'dom/DOMNamedFlowCollection.idl',
             'dom/NamedNodeMap.idl',
             'dom/Node.idl',
             'dom/NodeFilter.idl',
             'dom/NodeIterator.idl',
             'dom/NodeList.idl',
             'dom/Notation.idl',
             'dom/OverflowEvent.idl',
             'dom/PageTransitionEvent.idl',
+            'dom/PaintOrderLists.idl',
             'dom/PopStateEvent.idl',
             'dom/ProcessingInstruction.idl',
             'dom/ProgressEvent.idl',
             'dom/PropertyNodeList.idl',
             'dom/Range.idl',
             'dom/RangeException.idl',
             'dom/RequestAnimationFrameCallback.idl',
             'dom/SecurityPolicyViolationEvent.idl',
             'dom/ShadowRoot.idl',
             'dom/StringCallback.idl',
@@ skipping 6095 matching lines @@
           '<(SHARED_INTERMEDIATE_DIR)/WebCore/bindings/JSSVGZoomAndPan.cpp',
           '<(SHARED_INTERMEDIATE_DIR)/WebCore/bindings/JSSVGZoomAndPan.h',
           '<(SHARED_INTERMEDIATE_DIR)/WebCore/bindings/JSSVGZoomEvent.cpp',
           '<(SHARED_INTERMEDIATE_DIR)/WebCore/bindings/JSSVGZoomEvent.h',
         ],
         'export_file_generator_files': [
             '<(PRODUCT_DIR)/DerivedSources/WebCore/ExportFileGenerator.cpp',
         ],
     }
 }