Allocate CSSGlobalRuleSet on heap.

third_party/WebKit/Source/core/dom/StyleEngine.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 97 matching lines @@
   void ModifiedStyleSheetCandidateNode(Node&);
   void MediaQueriesChangedInScope(TreeScope&);
   void WatchedSelectorsChanged();
   void InitialViewportChanged();
   void ViewportRulesChanged();
   void HtmlImportAddedOrRemoved();
 
   void InjectAuthorSheet(StyleSheetContents* author_sheet);
   CSSStyleSheet& EnsureInspectorStyleSheet();
   RuleSet* WatchedSelectorsRuleSet() {
-    return global_rule_set_.WatchedSelectorsRuleSet();
+    DCHECK(IsMaster());
+    DCHECK(global_rule_set_);
+    return global_rule_set_->WatchedSelectorsRuleSet();
   }
   bool HasStyleSheets() const {
     return GetDocumentStyleSheetCollection().HasStyleSheets();
   }
 
   RuleSet* RuleSetForSheet(CSSStyleSheet&);
   void MediaQueryAffectingValueChanged();
   void UpdateStyleSheetsInImport(StyleEngine& master_engine,
                                  DocumentStyleSheetCollector& parent_collector);
   void UpdateActiveStyle();
@@ skipping 64 matching lines @@
       CreateResolver();
     return *resolver_;
   }
 
   bool HasResolver() const { return resolver_; }
 
   StyleInvalidator& GetStyleInvalidator() { return style_invalidator_; }
   bool MediaQueryAffectedByViewportChange();
   bool MediaQueryAffectedByDeviceChange();
   bool HasViewportDependentMediaQueries() const {
-    return !global_rule_set_.GetRuleFeatureSet()
+    DCHECK(IsMaster());
+    DCHECK(global_rule_set_);
+    return !global_rule_set_->GetRuleFeatureSet()
                 .ViewportDependentMediaQueryResults()
                 .IsEmpty();
   }
 
   CSSFontSelector* FontSelector() { return font_selector_; }
   void SetFontSelector(CSSFontSelector*);
 
   void RemoveFontFaceRules(const HeapVector<Member<const StyleRuleFontFace>>&);
   void ClearFontCache();
   // updateGenericFontFamilySettings is used from WebSettingsImpl.
@@ skipping 75 matching lines @@
   void MarkTreeScopeDirty(TreeScope&);
 
   bool IsMaster() const { return is_master_; }
   Document* Master();
   Document& GetDocument() const { return *document_; }
 
   typedef HeapHashSet<Member<TreeScope>> UnorderedTreeScopeSet;
 
   void MediaQueryAffectingValueChanged(UnorderedTreeScopeSet&);
   const RuleFeatureSet& GetRuleFeatureSet() const {
-    return global_rule_set_.GetRuleFeatureSet();
+    DCHECK(IsMaster());
+    DCHECK(global_rule_set_);
+    return global_rule_set_->GetRuleFeatureSet();
   }
 
   void CreateResolver();
   void ClearResolvers();
 
   CSSStyleSheet* ParseSheet(Element&,
                             const String& text,
                             TextPosition start_position);
 
   const DocumentStyleSheetCollection& GetDocumentStyleSheetCollection() const {
@@ skipping 15 matching lines @@
       Element&,
       const HeapHashSet<Member<RuleSet>>&);
   void ScheduleTypeRuleSetInvalidations(ContainerNode&,
                                         const HeapHashSet<Member<RuleSet>>&);
   void InvalidateSlottedElements(HTMLSlotElement&);
 
   void UpdateViewport();
   void UpdateActiveStyleSheets();
   void UpdateGlobalRuleSet() {
     DCHECK(!NeedsActiveStyleSheetUpdate());
-    global_rule_set_.Update(GetDocument());
+    if (global_rule_set_)
+      global_rule_set_->Update(GetDocument());
   }
   const MediaQueryEvaluator& EnsureMediaQueryEvaluator();
 
   Member<Document> document_;
   bool is_master_;
 
   // Track the number of currently loading top-level stylesheets needed for
   // layout.  Sheets loaded using the @import directive are not included in this
   // count.  We use this count of pending sheets to detect when we can begin
   // attaching elements and when it is safe to execute scripts.
@@ skipping 17 matching lines @@
   bool document_scope_dirty_ = true;
   bool all_tree_scopes_dirty_ = false;
   bool tree_scopes_removed_ = false;
   UnorderedTreeScopeSet dirty_tree_scopes_;
   UnorderedTreeScopeSet active_tree_scopes_;
   DocumentOrderedList tree_boundary_crossing_scopes_;
 
   String preferred_stylesheet_set_name_;
   String selected_stylesheet_set_name_;
 
-  CSSGlobalRuleSet global_rule_set_;
-
   bool uses_rem_units_ = false;
   bool ignore_pending_stylesheets_ = false;
 
   Member<StyleResolver> resolver_;
   Member<ViewportStyleResolver> viewport_resolver_;
   Member<MediaQueryEvaluator> media_query_evaluator_;
+  Member<CSSGlobalRuleSet> global_rule_set_;
   StyleInvalidator style_invalidator_;
 
   Member<CSSFontSelector> font_selector_;
 
   HeapHashMap<AtomicString, WeakMember<StyleSheetContents>>
       text_to_sheet_cache_;
   HeapHashMap<WeakMember<StyleSheetContents>, AtomicString>
       sheet_to_text_cache_;
 
   std::unique_ptr<StyleResolverStats> style_resolver_stats_;
   unsigned style_for_element_count_ = 0;
 
   friend class StyleEngineTest;
 };
 
 }  // namespace blink
 
 #endif