Remove more instances of BrowserThread::FILE.

extensions/shell/browser/shell_url_request_context_getter.cc

Index: extensions/shell/browser/shell_url_request_context_getter.cc
diff --git a/extensions/shell/browser/shell_url_request_context_getter.cc b/extensions/shell/browser/shell_url_request_context_getter.cc
index 654f468ca72b5de46fd8f80b1b83533eb309413f..757e53abfbe5950e81e1c2acf1e7659c0a9cf70c 100644
--- a/extensions/shell/browser/shell_url_request_context_getter.cc
+++ b/extensions/shell/browser/shell_url_request_context_getter.cc
@@ -18,7 +18,6 @@ ShellURLRequestContextGetter::ShellURLRequestContextGetter(
     bool ignore_certificate_errors,
     const base::FilePath& base_path,
     scoped_refptr<base::SingleThreadTaskRunner> io_task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> file_task_runner,
     content::ProtocolHandlerMap* protocol_handlers,
     content::URLRequestInterceptorScopedVector request_interceptors,
     net::NetLog* net_log,
@@ -26,7 +25,6 @@ ShellURLRequestContextGetter::ShellURLRequestContextGetter(
     : content::ShellURLRequestContextGetter(ignore_certificate_errors,
                                             base_path,
                                             std::move(io_task_runner),
-                                            std::move(file_task_runner),
                                             protocol_handlers,
                                             std::move(request_interceptors),
                                             net_log),