Remove BlobRegistry indirection since there is only one implementation.

BUG=

Review URL: https://chromiumcodereview.appspot.com/15851008

git-svn-id: svn://svn.chromium.org/blink/trunk@152746 bbb929c8-8fbe-4397-9dbb-9b2b20218538
    FileWriterHelperCallbacks(AsyncFileWriterClient* client, const KURL& path, WebKit::WebFileSystem* webFileSystem, PassOwnPtr<WebCore::AsyncFileSystemCallbacks> callbacks)
        : m_client(client)
        , m_path(path)
        , m_webFileSystem(webFileSystem)
        , m_callbacks(callbacks)
    {
    }

    FileWriterHelperCallbacks(AsyncFileWriterClient* client, const KURL& path, WebKit::WebFileSystem* webFileSystem, PassOwnPtr<WebCore::AsyncFileSystemCallbacks> callbacks)
        : m_client(client)
        , m_path(path)
        , m_webFileSystem(webFileSystem)
        , m_callbacks(callbacks)
    {
    }
