Add a deprecation message for shadow-piercing descendant combinators and shadow pseudo elements.

Source/core/css/parser/CSSSelectorParser.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/CSSSelectorParser.h"
 
 #include "core/css/CSSSelectorList.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/frame/UseCounter.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 static void recordSelectorStats(const CSSParserContext& context, const CSSSelectorList& selectorList)
 {
     if (!context.useCounter())
         return;
 
     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector)) {
         for (const CSSSelector* current = selector; current ; current = current->tagHistory()) {
             UseCounter::Feature feature = UseCounter::NumberOfFeatures;
             switch (current->pseudoType()) {
             case CSSSelector::PseudoUnresolved:
                 feature = UseCounter::CSSSelectorPseudoUnresolved;
                 break;
-            case CSSSelector::PseudoShadow:
-                feature = UseCounter::CSSSelectorPseudoShadow;
-                break;
             case CSSSelector::PseudoContent:
                 feature = UseCounter::CSSSelectorPseudoContent;
                 break;
             case CSSSelector::PseudoHost:
                 feature = UseCounter::CSSSelectorPseudoHost;
                 break;
             case CSSSelector::PseudoHostContext:
                 feature = UseCounter::CSSSelectorPseudoHostContext;
                 break;
             case CSSSelector::PseudoFullScreenDocument:
                 feature = UseCounter::CSSSelectorPseudoFullScreenDocument;
                 break;
             case CSSSelector::PseudoFullScreenAncestor:
                 feature = UseCounter::CSSSelectorPseudoFullScreenAncestor;
                 break;
             case CSSSelector::PseudoFullScreen:
                 feature = UseCounter::CSSSelectorPseudoFullScreen;
                 break;
             default:
                 break;
             }
             if (feature != UseCounter::NumberOfFeatures)
                 context.useCounter()->count(feature);
-            if (current->relation() == CSSSelector::ShadowDeep)
-                context.useCounter()->count(UseCounter::CSSDeepCombinator);
             if (current->selectorList())
                 recordSelectorStats(context, *current->selectorList());
         }
     }
 }
 
 void CSSSelectorParser::parseSelector(CSSParserTokenRange range, const CSSParserContext& context, const AtomicString& defaultNamespace, StyleSheetContents* styleSheet, CSSSelectorList& output)
 {
     CSSSelectorParser parser(context, defaultNamespace, styleSheet);
     range.consumeWhitespace();
@@ skipping 597 matching lines @@
         compoundSelector->insertTagHistory(CSSSelector::SubSelector, simpleSelector, relation);
         return compoundSelector;
     }
 
     // All other simple selectors are added to the end of the compound.
     compoundSelector->appendTagHistory(CSSSelector::SubSelector, simpleSelector);
     return compoundSelector;
 }
 
 } // namespace blink