FileSystem: Migrate ExecutionContextTask to WTF::Closure

third_party/WebKit/Source/modules/filesystem/DOMFileSystem.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 71 matching lines @@
 
   // ScriptWrappable overrides.
   bool hasPendingActivity() const final;
 
   void createWriter(const FileEntry*, FileWriterCallback*, ErrorCallbackBase*);
   void createFile(const FileEntry*, BlobCallback*, ErrorCallbackBase*);
 
   // Schedule a callback. This should not cross threads (should be called on the
   // same context thread).
   static void scheduleCallback(ExecutionContext* executionContext,
-                               std::unique_ptr<ExecutionContextTask> task) {
-    DCHECK(executionContext->isContextThread());
-    executionContext->postTask(TaskType::FileReading, BLINK_FROM_HERE,
-                               std::move(task), taskNameForInstrumentation());
-  }
+                               std::unique_ptr<WTF::Closure> task);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   DOMFileSystem(ExecutionContext*,
                 const String& name,
                 FileSystemType,
                 const KURL& rootURL);
 
   static String taskNameForInstrumentation() { return "FileSystem"; }
 
   int m_numberOfPendingCallbacks;
   Member<DirectoryEntry> m_rootEntry;
 };
 
 }  // namespace blink
 
 #endif  // DOMFileSystem_h