Drop empty list :host() and :host-context().

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 1450 matching lines @@
     | ':' 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 = $$->pseudoType();
         if (type != CSSSelector::PseudoHost)
             YYERROR;
     }
-    //  used by :host()
-    | ':' HOSTFUNCTION maybe_space closing_parenthesis {
-        $$ = parser->createFloatingSelector();
-        $$->setMatch(CSSSelector::PseudoClass);
-        parser->tokenToLowerCase($2);
-        $$->setValue($2.atomicSubstring(0, $2.length() - 1));
-        CSSSelector::PseudoType type = $$->pseudoType();
-        if (type != CSSSelector::PseudoHost)
-            YYERROR;
-    }
     | ':' HOSTFUNCTION selector_recovery closing_parenthesis {
         YYERROR;
     }
     //  used by :host-context()
     | ':' HOSTCONTEXTFUNCTION maybe_space simple_selector_list maybe_space closing_parenthesis {
         $$ = parser->createFloatingSelector();
         $$->setMatch(CSSSelector::PseudoClass);
         $$->adoptSelectorVector(*parser->sinkFloatingSelectorVector($4));
         parser->tokenToLowerCase($2);
         $$->setValue($2);
         CSSSelector::PseudoType type = $$->pseudoType();
         if (type != CSSSelector::PseudoHostContext)
             YYERROR;
     }
-    | ':' HOSTCONTEXTFUNCTION maybe_space closing_parenthesis {
-        $$ = parser->createFloatingSelector();
-        $$->setMatch(CSSSelector::PseudoClass);
-        parser->tokenToLowerCase($2);
-        $$->setValue($2.atomicSubstring(0, $2.length() - 1));
-        CSSSelector::PseudoType type = $$->pseudoType();
-        if (type != CSSSelector::PseudoHostContext)
-            YYERROR;
-    }
     | ':' HOSTCONTEXTFUNCTION selector_recovery closing_parenthesis {
         YYERROR;
     }
   ;
 
 selector_recovery:
     error error_location error_recovery;
 
 declaration_list:
     /* empty */ { $$ = false; }
@@ skipping 382 matching lines @@
     ;
 
 rule_error_recovery:
     /* empty */
   | rule_error_recovery error
   | rule_error_recovery invalid_square_brackets_block
   | rule_error_recovery invalid_parentheses_block
     ;
 
 %%