Reland: Refactor Script(Loader|Runner): don't access Resources all over the place...

Source/core/dom/PendingScript.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 namespace blink {
 
 PendingScript::~PendingScript()
 {
 }
 
 void PendingScript::watchForLoad(ScriptResourceClient* client)
 {
     ASSERT(!m_watchingForLoad);
-    ASSERT(!isReady());
+    // addClient() will call notifyFinished() if the load is complete. Callers
+    // who do not expect to be re-entered from this call should not call
+    // watchForLoad for a PendingScript which isReady. We also need to set
+    // m_watchingForLoad early, since addClient() can result in calling
+    // notifyFinished and further stopWatchingForLoad().
+    m_watchingForLoad = true;
     if (m_streamer) {
         m_streamer->addClient(client);
     } else {
-        // addClient() will call notifyFinished() if the load is
-        // complete. Callers do not expect to be re-entered from this call, so
-        // they should not become a client of an already-loaded Resource.
         resource()->addClient(client);
     }
-    m_watchingForLoad = true;
 }
 
 void PendingScript::stopWatchingForLoad(ScriptResourceClient* client)
 {
     if (!m_watchingForLoad)
         return;
     ASSERT(resource());
     if (m_streamer) {
-        m_streamer->cancel();
         m_streamer->removeClient(client);
-        m_streamer.clear();
     } else {
         resource()->removeClient(client);
     }
     m_watchingForLoad = false;
 }
 
 PassRefPtrWillBeRawPtr<Element> PendingScript::releaseElementAndClear()
 {
     setScriptResource(0);
     m_watchingForLoad = false;
     m_startingPosition = TextPosition::belowRangePosition();
+    if (m_streamer)
+        m_streamer->cancel();
     m_streamer.release();
     return m_element.release();
 }
 
 void PendingScript::setScriptResource(ScriptResource* resource)
 {
     setResource(resource);
 }
 
 void PendingScript::notifyFinished(Resource* resource)
@@ skipping 29 matching lines @@
 bool PendingScript::isReady() const
 {
     if (resource() && !resource()->isLoaded())
         return false;
     if (m_streamer && !m_streamer->isFinished())
         return false;
     return true;
 }
 
 }