Teach ScriptRunner how to yield and post on loading task queue

Source/core/dom/ScriptLoader.h

 /*
  * Copyright (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 18 matching lines @@
 #include "wtf/text/TextPosition.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class Element;
 class ScriptLoaderClient;
 class ScriptSourceCode;
 
 
-class ScriptLoader final : public NoBaseWillBeGarbageCollectedFinalized<ScriptLoader>, private ScriptResourceClient {
+class ScriptLoader : public NoBaseWillBeGarbageCollectedFinalized<ScriptLoader>, private ScriptResourceClient {
 public:
     static PassOwnPtrWillBeRawPtr<ScriptLoader> create(Element* element, bool createdByParser, bool isEvaluated)
     {
         return adoptPtrWillBeNoop(new ScriptLoader(element, createdByParser, isEvaluated));
     }
 
     virtual ~ScriptLoader();
     DECLARE_VIRTUAL_TRACE();
 
     Element* element() const { return m_element; }
 
     enum LegacyTypeSupport { DisallowLegacyTypeInTypeAttribute, AllowLegacyTypeInTypeAttribute };
     bool prepareScript(const TextPosition& scriptStartPosition = TextPosition::minimumPosition(), LegacyTypeSupport = DisallowLegacyTypeInTypeAttribute);
 
     String scriptCharset() const { return m_characterEncoding; }
     String scriptContent() const;
     void executeScript(const ScriptSourceCode&, double* compilationFinishTime = 0);
-    void execute();
+    virtual void execute();
 
     // XML parser calls these
     void dispatchLoadEvent();
     void dispatchErrorEvent();
     bool isScriptTypeSupported(LegacyTypeSupport) const;
 
     bool haveFiredLoadEvent() const { return m_haveFiredLoad; }
     bool willBeParserExecuted() const { return m_willBeParserExecuted; }
     bool readyToBeParserExecuted() const { return m_readyToBeParserExecuted; }
     bool willExecuteWhenDocumentFinishedParsing() const { return m_willExecuteWhenDocumentFinishedParsing; }
     ResourcePtr<ScriptResource> resource() { return m_resource; }
 
     void setHaveFiredLoadEvent(bool haveFiredLoad) { m_haveFiredLoad = haveFiredLoad; }
     bool isParserInserted() const { return m_parserInserted; }
     bool alreadyStarted() const { return m_alreadyStarted; }
     bool forceAsync() const { return m_forceAsync; }
 
     // Helper functions used by our parent classes.
     void didNotifySubtreeInsertionsToDocument();
     void childrenChanged();
     void handleSourceAttribute(const String& sourceUrl);
     void handleAsyncAttribute();
 
-    bool isReady() const { return m_pendingScript.isReady(); }
+    virtual bool isReady() const { return m_pendingScript.isReady(); }
 
     // Clears the connection to the PendingScript (and Element and Resource).
     void detach();
 
-private:
+protected:
     ScriptLoader(Element*, bool createdByParser, bool isEvaluated);
 
+private:
     bool ignoresLoadRequest() const;
     bool isScriptForEventSupported() const;
 
     bool fetchScript(const String& sourceUrl, FetchRequest::DeferOption);
 
     ScriptLoaderClient* client() const;
 
     // ResourceClient
     virtual void notifyFinished(Resource*) override;
 
@@ skipping 14 matching lines @@
     bool m_willExecuteWhenDocumentFinishedParsing : 1;
     bool m_forceAsync : 1;
     bool m_willExecuteInOrder : 1;
 };
 
 ScriptLoader* toScriptLoaderIfPossible(Element*);
 
 } // namespace blink
 
 #endif // ScriptLoader_h