Current work-in-progress crbug.com/567021

third_party/WebKit/Source/core/css/CSSGlobalRuleSet.cpp

+// Copyright 2016 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 "core/css/CSSGlobalRuleSet.h"
+
+#include "core/css/CSSDefaultStyleSheets.h"
+#include "core/css/RuleSet.h"
+#include "core/dom/CSSSelectorWatch.h"
+#include "core/dom/Document.h"
+#include "core/dom/StyleEngine.h"
+
+namespace blink {
+
+void CSSGlobalRuleSet::initWatchedSelectorsRuleSet(Document& document)
+{
+    m_watchedSelectorsRuleSet = nullptr;
+    CSSSelectorWatch* watch = CSSSelectorWatch::fromIfExists(document);
+    if (!watch)
+        return;
+    const HeapVector<Member<StyleRule>>& watchedSelectors = watch->watchedCallbackSelectors();
+    if (!watchedSelectors.size())
+        return;
+    m_watchedSelectorsRuleSet = RuleSet::create();
+    for (unsigned i = 0; i < watchedSelectors.size(); ++i)
+        m_watchedSelectorsRuleSet->addStyleRule(watchedSelectors[i].get(), RuleHasNoSpecialState);
+}
+
+static RuleSet* makeRuleSet(const HeapVector<RuleFeature>& rules)
+{
+    size_t size = rules.size();
+    if (!size)
+        return nullptr;
+    RuleSet* ruleSet = RuleSet::create();
+    for (size_t i = 0; i < size; ++i)
+        ruleSet->addRule(rules[i].rule, rules[i].selectorIndex, rules[i].hasDocumentSecurityOrigin ? RuleHasDocumentSecurityOrigin : RuleHasNoSpecialState);
+    return ruleSet;
+}
+
+void CSSGlobalRuleSet::update(Document& document)
+{
+    m_features.clear();
+
+    CSSDefaultStyleSheets& defaultStyleSheets = CSSDefaultStyleSheets::instance();
+    if (defaultStyleSheets.defaultStyle())
+        m_features.add(defaultStyleSheets.defaultStyle()->features());
+
+    if (document.isViewSource())
+        m_features.add(defaultStyleSheets.defaultViewSourceStyle()->features());
+
+    if (m_watchedSelectorsRuleSet)
+        m_features.add(m_watchedSelectorsRuleSet->features());
+
+    document.styleEngine().collectScopedStyleFeaturesTo(m_features);
+
+    m_siblingRuleSet = makeRuleSet(m_features.siblingRules);
+    m_uncommonAttributeRuleSet = makeRuleSet(m_features.uncommonAttributeRules);
+}
+
+DEFINE_TRACE(CSSGlobalRuleSet)
+{
+    visitor->trace(m_features);
+    visitor->trace(m_siblingRuleSet);
+    visitor->trace(m_uncommonAttributeRuleSet);
+    visitor->trace(m_watchedSelectorsRuleSet);
+}
+
+} // namespace blink