Revert of Revert of Split out CSSParser public API

Source/core/html/HTMLContentElement.cpp

Index: Source/core/html/HTMLContentElement.cpp
diff --git a/Source/core/html/HTMLContentElement.cpp b/Source/core/html/HTMLContentElement.cpp
index 7c0cb2af3b66413641b912dff8590946cb863791..20486eac61853b0ef1d59303a3e4c86476d685b3 100644
--- a/Source/core/html/HTMLContentElement.cpp
+++ b/Source/core/html/HTMLContentElement.cpp
@@ -30,7 +30,7 @@
 #include "core/HTMLNames.h"
 #include "core/css/SelectorChecker.h"
 #include "core/css/SiblingTraversalStrategies.h"
-#include "core/css/parser/BisonCSSParser.h"
+#include "core/css/parser/CSSParser.h"
 #include "core/dom/QualifiedName.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/ShadowRoot.h"
@@ -57,7 +57,7 @@
 {
     ASSERT(m_shouldParseSelect);
 
-    BisonCSSParser parser(CSSParserContext(document(), 0));
+    CSSParser parser(CSSParserContext(document(), 0));
     parser.parseSelector(m_select, m_selectorList);
     m_shouldParseSelect = false;
     m_isValidSelector = validateSelect();