CSS Parser: Support CDO and CDC tokens (<!--, -->)

Source/core/css/parser/CSSParserImpl.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/parser/CSSParserImpl.h"
 
 #include "core/css/CSSKeyframesRule.h"
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/StylePropertySet.h"
@@ skipping 141 matching lines @@
     while (!range.atEnd()) {
         switch (range.peek().type()) {
         case WhitespaceToken:
         case CommentToken:
             range.consumeWhitespaceAndComments();
             break;
         case AtKeywordToken:
             if (PassRefPtrWillBeRawPtr<StyleRuleBase> rule = consumeAtRule(range, allowedRules))
                 result.append(rule);
             break;
+        case CDOToken:
+        case CDCToken:
+            if (ruleListType == TopLevelRuleList) {
+                range.consume();
+                break;
+            }
+            // fallthrough
         default:
-            // FIXME: TopLevelRuleList should skip <CDO-token> and <CDC-token>
             if (PassRefPtrWillBeRawPtr<StyleRuleBase> rule = consumeQualifiedRule(range, allowedRules))
                 result.append(rule);
             break;
         }
     }
 
     return result;
 }
 
 PassRefPtrWillBeRawPtr<StyleRuleBase> CSSParserImpl::consumeAtRule(CSSParserTokenRange& range, AllowedRulesType& allowedRules)
@@ skipping 294 matching lines @@
         else
             return nullptr; // Parser error, invalid value in keyframe selector
         if (range.atEnd())
             return result.release();
         if (range.consume().type() != CommaToken)
             return nullptr; // Parser error
     }
 }
 
 } // namespace blink