Tried using CrossThreadPersistent for workerDebuggerAgents

Source/core/inspector/InspectorCSSAgent.h

Index: Source/core/inspector/InspectorCSSAgent.h
diff --git a/Source/core/inspector/InspectorCSSAgent.h b/Source/core/inspector/InspectorCSSAgent.h
index 6861486ccdc875478e3fc5de1f5a1337403f1538..210fc6dbbedece61333abf31224088151977137f 100644
--- a/Source/core/inspector/InspectorCSSAgent.h
+++ b/Source/core/inspector/InspectorCSSAgent.h
@@ -97,11 +97,12 @@ public:
 
     static CSSStyleRule* asCSSStyleRule(CSSRule*);
 
-    static PassOwnPtr<InspectorCSSAgent> create(InspectorDOMAgent* domAgent, InspectorPageAgent* pageAgent, InspectorResourceAgent* resourceAgent)
+    static PassOwnPtrWillBeRawPtr<InspectorCSSAgent> create(InspectorDOMAgent* domAgent, InspectorPageAgent* pageAgent, InspectorResourceAgent* resourceAgent)
     {
-        return adoptPtr(new InspectorCSSAgent(domAgent, pageAgent, resourceAgent));
+        return adoptPtrWillBeNoop(new InspectorCSSAgent(domAgent, pageAgent, resourceAgent));
     }
     virtual ~InspectorCSSAgent();
+    virtual void trace(Visitor*) OVERRIDE;
 
     bool forcePseudoState(Element*, CSSSelector::PseudoType);
     virtual void setFrontend(InspectorFrontend*) OVERRIDE;
@@ -148,9 +149,9 @@ private:
 
     InspectorCSSAgent(InspectorDOMAgent*, InspectorPageAgent*, InspectorResourceAgent*);
 
-    typedef HashMap<String, RefPtr<InspectorStyleSheet> > IdToInspectorStyleSheet;
-    typedef HashMap<String, RefPtr<InspectorStyleSheetForInlineStyle> > IdToInspectorStyleSheetForInlineStyle;
-    typedef HashMap<Node*, RefPtr<InspectorStyleSheetForInlineStyle> > NodeToInspectorStyleSheet; // bogus "stylesheets" with elements' inline styles
+    typedef WillBeHeapHashMap<String, RefPtrWillBeMember<InspectorStyleSheet> > IdToInspectorStyleSheet;
+    typedef WillBeHeapHashMap<String, RefPtrWillBeMember<InspectorStyleSheetForInlineStyle> > IdToInspectorStyleSheetForInlineStyle;
+    typedef WillBeHeapHashMap<Node*, RefPtrWillBeMember<InspectorStyleSheetForInlineStyle> > NodeToInspectorStyleSheet; // bogus "stylesheets" with elements' inline styles
     typedef HashMap<int, unsigned> NodeIdToForcedPseudoState;
 
     void wasEnabled(PassRefPtr<EnableCallback>);
@@ -192,22 +193,22 @@ private:
     void resetPseudoStates();
 
     InspectorFrontend::CSS* m_frontend;
-    InspectorDOMAgent* m_domAgent;
-    InspectorPageAgent* m_pageAgent;
-    InspectorResourceAgent* m_resourceAgent;
+    RawPtrWillBeMember<InspectorDOMAgent> m_domAgent;
+    RawPtrWillBeMember<InspectorPageAgent> m_pageAgent;
+    RawPtrWillBeMember<InspectorResourceAgent> m_resourceAgent;
 
     IdToInspectorStyleSheet m_idToInspectorStyleSheet;
     IdToInspectorStyleSheetForInlineStyle m_idToInspectorStyleSheetForInlineStyle;
-    HashMap<CSSStyleSheet*, RefPtr<InspectorStyleSheet> > m_cssStyleSheetToInspectorStyleSheet;
+    WillBeHeapHashMap<CSSStyleSheet*, RefPtrWillBeMember<InspectorStyleSheet> > m_cssStyleSheetToInspectorStyleSheet;
     typedef HashMap<Document*, OwnPtr<HashSet<CSSStyleSheet*> > > DocumentStyleSheets;
     DocumentStyleSheets m_documentToCSSStyleSheets;
     HashSet<Document*> m_invalidatedDocuments;
 
     NodeToInspectorStyleSheet m_nodeToInspectorStyleSheet;
-    HashMap<RefPtr<Document>, RefPtr<InspectorStyleSheet> > m_documentToViaInspectorStyleSheet; // "via inspector" stylesheets
+    HashMap<RefPtr<Document>, RefPtrWillBeMember<InspectorStyleSheet> > m_documentToViaInspectorStyleSheet; // "via inspector" stylesheets
     NodeIdToForcedPseudoState m_nodeIdToForcedPseudoState;
 
-    RefPtrWillBePersistent<CSSStyleSheet> m_inspectorUserAgentStyleSheet;
+    RefPtrWillBeMember<CSSStyleSheet> m_inspectorUserAgentStyleSheet;
 
     int m_lastStyleSheetId;
     int m_styleSheetsPendingMutation;