Split out CSSParser public API

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/AnimationPlayer.idl',
@@ skipping 905 matching lines @@
             'css/StyleSheetList.h',
             'css/TreeBoundaryCrossingRules.cpp',
             'css/TreeBoundaryCrossingRules.h',
             'css/invalidation/DescendantInvalidationSet.cpp',
             'css/invalidation/DescendantInvalidationSet.h',
             'css/invalidation/StyleInvalidator.cpp',
             'css/invalidation/StyleInvalidator.h',
             'css/invalidation/StyleSheetInvalidationAnalysis.cpp',
             'css/invalidation/StyleSheetInvalidationAnalysis.h',
             'css/parser/BisonCSSParser.h',
+            'css/parser/CSSParser.cpp',
+            'css/parser/CSSParser.h',
             'css/parser/CSSParserMode.cpp',
             'css/parser/CSSParserMode.h',
             'css/parser/CSSParserValues.cpp',
             'css/parser/CSSPropertyParser.cpp',
             'css/parser/CSSPropertyParser.h',
             'css/parser/CSSTokenizer.h',
             'css/parser/MediaQueryBlockWatcher.cpp',
             'css/parser/MediaQueryInputStream.cpp',
             'css/parser/MediaQueryParser.cpp',
             'css/parser/SizesCalcParser.cpp',
@@ skipping 2571 matching lines @@
             'rendering/shapes/BoxShapeTest.cpp',
             'rendering/style/OutlineValueTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }