Improve CancellableTaskFactory handling and Oilpan usage.

Source/core/dom/ScriptRunner.h

Index: Source/core/dom/ScriptRunner.h
diff --git a/Source/core/dom/ScriptRunner.h b/Source/core/dom/ScriptRunner.h
index f2e64526f576bf4f2a240e3657f656bac923c8f4..5a3d66d1c358cd08c12d0f1d2111cef57188b721 100644
--- a/Source/core/dom/ScriptRunner.h
+++ b/Source/core/dom/ScriptRunner.h
@@ -29,7 +29,6 @@
 #include "core/CoreExport.h"
 #include "core/fetch/ResourcePtr.h"
 #include "platform/heap/Handle.h"
-#include "platform/scheduler/CancellableTaskFactory.h"
 #include "wtf/Deque.h"
 #include "wtf/HashMap.h"
 #include "wtf/Noncopyable.h"
@@ -37,6 +36,7 @@
 
 namespace blink {
 
+class CancellableTaskFactory;
 class Document;
 class ScriptLoader;
 
@@ -79,7 +79,7 @@ private:
     // http://www.whatwg.org/specs/web-apps/current-work/#set-of-scripts-that-will-execute-as-soon-as-possible
     WillBeHeapDeque<RawPtrWillBeMember<ScriptLoader>> m_scriptsToExecuteSoon;
     WillBeHeapHashSet<RawPtrWillBeMember<ScriptLoader>> m_pendingAsyncScripts;
-    CancellableTaskFactory m_executeScriptsTaskFactory;
+    OwnPtr<CancellableTaskFactory> m_executeScriptsTaskFactory;
 };
 
 }