Make WebFileSystemCallbacks not self-destruct, deprecate AsyncFileSystem

Source/modules/filesystem/DOMFileSystem.h

Index: Source/modules/filesystem/DOMFileSystem.h
diff --git a/Source/modules/filesystem/DOMFileSystem.h b/Source/modules/filesystem/DOMFileSystem.h
index 4f334222e6dc661f31f38753b5c4f2b105773016..76ee96c4c5f6f80356080a9277e8660df2300d5a 100644
--- a/Source/modules/filesystem/DOMFileSystem.h
+++ b/Source/modules/filesystem/DOMFileSystem.h
@@ -47,17 +47,19 @@ class FileWriterCallback;
 
 class DOMFileSystem : public DOMFileSystemBase, public ScriptWrappable, public ActiveDOMObject {
 public:
-    static PassRefPtr<DOMFileSystem> create(ScriptExecutionContext*, const String& name, FileSystemType, const KURL& rootURL, PassOwnPtr<AsyncFileSystem>);
+    static PassRefPtr<DOMFileSystem> create(ScriptExecutionContext*, const String& name, FileSystemType, const KURL& rootURL);
 
     // Creates a new isolated file system for the given filesystemId.
     static PassRefPtr<DOMFileSystem> createIsolatedFileSystem(ScriptExecutionContext*, const String& filesystemId);
 
     PassRefPtr<DirectoryEntry> root();
 
-    // ActiveDOMObject methods.
-    virtual void stop();
-    virtual bool hasPendingActivity() const;
-    virtual void contextDestroyed();
+    // DOMFileSystemBase overrides.
+    virtual void addPendingCallbacks() OVERRIDE;
+    virtual void removePendingCallbacks() OVERRIDE;
+
+    // ActiveDOMObject overrides.
+    virtual bool hasPendingActivity() const OVERRIDE;
 
     void createWriter(const FileEntry*, PassRefPtr<FileWriterCallback>, PassRefPtr<ErrorCallback>);
     void createFile(const FileEntry*, PassRefPtr<FileCallback>, PassRefPtr<ErrorCallback>);
@@ -83,7 +85,7 @@ public:
     }
 
 private:
-    DOMFileSystem(ScriptExecutionContext*, const String& name, FileSystemType, const KURL& rootURL, PassOwnPtr<AsyncFileSystem>);
+    DOMFileSystem(ScriptExecutionContext*, const String& name, FileSystemType, const KURL& rootURL);
 
     // A helper template to schedule a callback task.
     template <typename CB, typename CBArg>
@@ -123,6 +125,8 @@ private:
         RefPtr<CB> m_callback;
         CBArg m_callbackArg;
     };
+
+    int m_pendingCallbacks;
 };
 
 template <typename CB, typename CBArg>