Explore the possibility of implementing the CSS Region interface.

Source/core/core.gypi

 {
     'variables': {
         'core_idl_files': [
             'css/CSS.idl',
             'css/CSSCharsetRule.idl',
             'css/CSSFontFaceLoadEvent.idl',
             'css/CSSFontFaceRule.idl',
             'css/CSSHostRule.idl',
             'css/CSSImportRule.idl',
             'css/CSSKeyframeRule.idl',
             'css/CSSKeyframesRule.idl',
             'css/CSSMediaRule.idl',
             'css/CSSPageRule.idl',
             'css/CSSPrimitiveValue.idl',
+            'css/CSSRegion.idl', 
             'css/CSSRule.idl',
             'css/CSSRuleList.idl',
             'css/CSSStyleDeclaration.idl',
             'css/CSSStyleRule.idl',
             'css/CSSStyleSheet.idl',
             'css/CSSSupportsRule.idl',
             # We should probably add CSSUnknownRule.idl to this list,
             # but it currently causes a compile error.
             # 'css/CSSUnknownRule.idl',
             'css/CSSValue.idl',
@@ skipping 47 matching lines @@
             'dom/MutationRecord.idl',
             'dom/NamedNodeMap.idl',
             'dom/Node.idl',
             'dom/NodeFilter.idl',
             'dom/NodeIterator.idl',
             'dom/NodeList.idl',
             'dom/Notation.idl',
             'dom/ParentNode.idl',
             'dom/ProcessingInstruction.idl',
             'dom/Promise.idl',
+            'dom/PseudoElement.idl',
             'dom/Range.idl',
             'dom/RequestAnimationFrameCallback.idl',
             'dom/StringCallback.idl',
             'dom/Text.idl',
             'dom/Touch.idl',
             'dom/TouchList.idl',
             'dom/TreeWalker.idl',
             'dom/URL.idl',
             'dom/URLUtils.idl',
             'dom/URLUtilsReadOnly.idl',
@@ skipping 580 matching lines @@
             'css/CSSPageRule.cpp',
             'css/CSSPageRule.h',
             'css/CSSParser.h',
             'css/CSSParserMode.h',
             'css/CSSParserValues.cpp',
             'css/CSSPrimitiveValue.cpp',
             'css/CSSPrimitiveValueMappings.h',
             'css/CSSProperty.cpp',
             'css/CSSPropertySourceData.cpp',
             'css/CSSReflectValue.cpp',
+            'css/CSSRegion.h',
             'css/CSSRegionRule.cpp',
             'css/CSSRegionRule.h',
             'css/CSSRule.cpp',
             'css/CSSRule.h',
             'css/CSSRuleList.cpp',
             'css/CSSRuleList.h',
             'css/CSSSegmentedFontFace.cpp',
             'css/CSSSegmentedFontFace.h',
             'css/CSSSegmentedFontFaceCache.cpp',
             'css/CSSSegmentedFontFaceCache.h',
@@ skipping 2933 matching lines @@
                 'bison_exe': 'bison',
                 # We specify a preprocess so it happens locally and won't get
                 # distributed to goma.
                 # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
                 # use /usr/bin/clang once we require Xcode 4.x.
                 'preprocessor': '--preprocessor "/usr/bin/gcc -E -P -x c++"'
               }],
          ],
     }
 }