Renamed :host to :ancestor and made :host to match only shadow host.

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 96 matching lines @@
     case STRING:
     case NTH:
     case HEX:
     case IDSEL:
     case DIMEN:
     case INVALIDDIMEN:
     case URI:
     case FUNCTION:
     case ANYFUNCTION:
     case HOSTFUNCTION:
+    case ANCESTORFUNCTION:
     case NOTFUNCTION:
     case CALCFUNCTION:
     case MINFUNCTION:
     case MAXFUNCTION:
     case VARFUNCTION:
     case VAR_DEFINITION:
     case UNICODERANGE:
         return true;
     default:
         return false;
@@ skipping 135 matching lines @@
 %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> HOSTFUNCTION
+%token <string> ANCESTORFUNCTION
 
 %token <string> UNICODERANGE
 
 %type <relation> combinator
 
 %type <rule> ruleset
 %type <rule> media
 %type <rule> import
 %type <rule> namespace
 %type <rule> page
@@ skipping 1253 matching lines @@
         $$->setMatch(CSSSelector::PseudoClass);
         parser->tokenToLowerCase($2);
         $$->setValue($2.atomicSubstring(0, $2.length() - 1));
         CSSSelector::PseudoType type = $$->pseudoType();
         if (type != CSSSelector::PseudoHost)
             YYERROR;
     }
     | ':' HOSTFUNCTION selector_recovery closing_parenthesis {
         YYERROR;
     }
+    | ':' ANCESTORFUNCTION maybe_space simple_selector_list maybe_space closing_parenthesis {
+        $$ = parser->createFloatingSelector();
+        $$->setMatch(CSSSelector::PseudoClass);
+        $$->adoptSelectorVector(*parser->sinkFloatingSelectorVector($4));
+        parser->tokenToLowerCase($2);
+        $$->setValue($2);
+        CSSSelector::PseudoType type = $$->pseudoType();
+        if (type != CSSSelector::PseudoAncestor)
+            YYERROR;
+    }
+    //  used by :ancestor()
+    | ':' ANCESTORFUNCTION 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::PseudoAncestor)
+            YYERROR;
+    }
+    | ':' ANCESTORFUNCTION selector_recovery closing_parenthesis {
+        YYERROR;
+    }
   ;
 
 selector_recovery:
     error error_location error_recovery;
 
 declaration_list:
     /* empty */ { $$ = false; }
     | declaration
     | decl_list declaration {
         $$ = $1 || $2;
@@ skipping 400 matching lines @@
 
 rule_error_recovery:
     /* empty */
   | rule_error_recovery error
   | rule_error_recovery invalid_square_brackets_block
   | rule_error_recovery invalid_parentheses_block
     ;
 
 %%