Remove CSSRule.UNKNOWN_RULE and CSSUnknownRule interface

Source/core/css/CSSRule.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2006, 2007, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Andreas Kling (kling@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 23 matching lines @@
 class CSSRuleList;
 class CSSStyleSheet;
 class StyleRuleBase;
 
 class CSSRule : public RefCountedWillBeGarbageCollectedFinalized<CSSRule>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     virtual ~CSSRule() { }
 
     enum Type {
-        UNKNOWN_RULE,
-        STYLE_RULE,
+        STYLE_RULE = 1,

[philipj_slow, 2015/06/10 13:34:21]

Can you spell out the constant for every case to match CSSRule.idl? Especially
since the last two entries have them this starts to look strange.

[Sunil Ratnu, 2015/06/10 13:54:40]

Done.

         CHARSET_RULE,
         IMPORT_RULE,
         MEDIA_RULE,
         FONT_FACE_RULE,
         PAGE_RULE,
         // 7 was VARIABLES_RULE; we now match other browsers with 7 as

[philipj_slow, 2015/06/10 13:34:21]

I think you can remove this comment too, this was fixed a long time ago...

[Sunil Ratnu, 2015/06/10 13:54:40]

Done.

         // KEYFRAMES_RULE:
         // <https://bugs.webkit.org/show_bug.cgi?id=71293>.
         KEYFRAMES_RULE,
         WEBKIT_KEYFRAMES_RULE = KEYFRAMES_RULE,
         KEYFRAME_RULE,
         WEBKIT_KEYFRAME_RULE = KEYFRAME_RULE,
         SUPPORTS_RULE = 12,
         VIEWPORT_RULE = 15,
     };
 
@@ skipping 52 matching lines @@
         CSSStyleSheet* m_parentStyleSheet;
     };
 };
 
 #define DEFINE_CSS_RULE_TYPE_CASTS(ToType, TYPE_NAME) \
     DEFINE_TYPE_CASTS(ToType, CSSRule, rule, rule->type() == CSSRule::TYPE_NAME, rule.type() == CSSRule::TYPE_NAME)
 
 } // namespace blink
 
 #endif // CSSRule_h