[Layout API] Create api/LayoutLIItem and use it in html/HTMLLIElement

third_party/WebKit/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 490 matching lines @@
         ],
         'webcore_rendering_files': [
             'layout/api/HitTestAction.h',
             'layout/api/LayoutBlockItem.h',
             'layout/api/LayoutBoxItem.h',
             'layout/api/LayoutBoxModel.h',
             'layout/api/LayoutEmbeddedItem.h',
             'layout/api/LayoutFullScreenItem.h',
             'layout/api/LayoutImageItem.h',
             'layout/api/LayoutItem.h',
+            'layout/api/LayoutLIItem.h',
             'layout/api/LayoutPartItem.h',
             'layout/api/LayoutTextControlItem.h',
             'layout/api/LayoutTextFragmentItem.h',
             'layout/api/LayoutTextItem.h',
             'layout/api/LineLayoutAPIShim.h',
             'layout/api/LineLayoutBlockFlow.h',
             'layout/api/LineLayoutBox.h',
             'layout/api/LineLayoutBoxModel.h',
             'layout/api/LineLayoutInline.h',
             'layout/api/LineLayoutItem.h',
@@ skipping 3531 matching lines @@
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }