Uses mojom module names as Dart's package: import URI

mojo/services/files/public/interfaces/files.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+[DartUriBase="mojo/services/files/public/interfaces"]
 module mojo.files;
 
 import "files/public/interfaces/directory.mojom";
 import "files/public/interfaces/types.mojom";
 
 enum FileSystem {
   // A per-instance (i.e., one for each call to |OpenFileSystem()|) temporary
   // file system.
   TEMPORARY,
 
   // A persistent, shared file system (rooted at ~/MojoDebug, which must already
   // exist) only available in Debug builds.
   DEBUG,
 };
 
 interface Files {
   OpenFileSystem(FileSystem file_system, Directory& directory) => (Error error);
 };