Fix serialization of content property to always quote

Source/core/css/parser/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 1609 matching lines @@
 operator:
     slash_operator
   | ',' maybe_space {
         $$ = ',';
     }
   ;
 
 term:
   unary_term maybe_space
   | unary_operator unary_term maybe_space { $$ = $2; $$.fValue *= $1; }
-  | STRING maybe_space { $$.id = CSSValueInvalid; $$.isInt = false; $$.string = $1; $$.unit = CSSPrimitiveValue::CSS_STRING; }
+  | STRING maybe_space { $$.id = CSSValueInvalid; $$.isInt = false; $$.string = $1; $$.unit = CSSPrimitiveValue::CSS_CUSTOM_IDENT; }

[Timothy Loh, 2015/03/03 23:20:15]

These are still <string>s though, right?

   | IDENT maybe_space { $$ = makeIdentValue($1); }
   /* We might need to actually parse the number from a dimension, but we can't just put something that uses $$.string into unary_term. */
   | DIMEN maybe_space { $$.id = CSSValueInvalid; $$.string = $1; $$.isInt = false; $$.unit = CSSParserValue::Dimension; }
   | unary_operator DIMEN maybe_space { $$.id = CSSValueInvalid; $$.string = $2; $$.isInt = false; $$.unit = CSSParserValue::Dimension; }
   | URI maybe_space { $$.id = CSSValueInvalid; $$.string = $1; $$.isInt = false; $$.unit = CSSPrimitiveValue::CSS_URI; }
   | UNICODERANGE maybe_space { $$.id = CSSValueInvalid; $$.string = $1; $$.isInt = false; $$.unit = CSSPrimitiveValue::CSS_UNICODE_RANGE; }
   | HEX maybe_space { $$.id = CSSValueInvalid; $$.string = $1; $$.isInt = false; $$.unit = CSSParserValue::HexColor; }
   | '#' maybe_space { $$.id = CSSValueInvalid; $$.string = CSSParserString(); $$.isInt = false; $$.unit = CSSParserValue::HexColor; } /* Handle error case: "color: #;" */
   /* FIXME: according to the specs a function can have a unary_operator in front. I know no case where this makes sense */
   | function maybe_space
@@ skipping 216 matching lines @@
     ;
 
 rule_error_recovery:
     /* empty */
   | rule_error_recovery error
   | rule_error_recovery invalid_square_brackets_block
   | rule_error_recovery invalid_parentheses_block
     ;
 
 %%