Remove ::part.

Source/core/css/CSSGrammar.y

 %{
 
 /*
  *  Copyright (C) 2002-2003 Lars Knoll (knoll@kde.org)
  *  Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  *  Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *  Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  *  Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
@@ skipping 243 matching lines @@
 %token <string> FUNCTION
 %token <string> ANYFUNCTION
 %token <string> CUEFUNCTION
 %token <string> NOTFUNCTION
 %token <string> DISTRIBUTEDFUNCTION
 %token <string> CALCFUNCTION
 %token <string> MINFUNCTION
 %token <string> MAXFUNCTION
 %token <string> VARFUNCTION
 %token <string> VAR_DEFINITION
-%token <string> PARTFUNCTION
 %token <string> HOSTFUNCTION
 
 %token <string> UNICODERANGE
 
 %type <relation> combinator
 
 %type <rule> ruleset
 %type <rule> media
 %type <rule> import
 %type <rule> namespace
@@ skipping 1270 matching lines @@
             selectorVector.append(parser->sinkFloatingSelector($4));
             $$->adoptSelectorVector(selectorVector);
 
             parser->tokenToLowerCase($2);
             $$->setValue($2);
         }
     }
     | ':' NOTFUNCTION selector_recovery closing_parenthesis {
         YYERROR;
     }
-    | ':' ':' PARTFUNCTION maybe_space IDENT maybe_space closing_parenthesis {
-        $$ = parser->createFloatingSelector();
-        $$->setMatch(CSSSelector::PseudoElement);
-        $$->setArgument($5);
-        if ($5.startsWithIgnoringCase("-webkit"))
-            $$->setMatchUserAgentOnly();
-        parser->tokenToLowerCase($3);
-        $$->setValue($3);
-        CSSSelector::PseudoType type = $$->pseudoType();
-        if (type != CSSSelector::PseudoPart)
-            YYERROR;
-    }
-    | ':' ':' PARTFUNCTION selector_recovery closing_parenthesis {
-        YYERROR;
-    }
     | ':' HOSTFUNCTION maybe_space simple_selector_list maybe_space closing_parenthesis {
         $$ = parser->createFloatingSelector();
         $$->setMatch(CSSSelector::PseudoClass);
         $$->adoptSelectorVector(*parser->sinkFloatingSelectorVector($4));
         parser->tokenToLowerCase($2);
         $$->setValue($2);
         CSSSelector::PseudoType type = $$->pseudoType();
         if (type != CSSSelector::PseudoHost)
             YYERROR;
     }
@@ skipping 397 matching lines @@
 
 rule_error_recovery:
     /* empty */
   | rule_error_recovery error
   | rule_error_recovery invalid_square_brackets_block
   | rule_error_recovery invalid_parentheses_block
     ;
 
 %%