Adding URLResponse Disk Cache to mojo.

mojo/services/service_cache/public/interfaces/service_cache.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.
+
+module mojo.service_cache;
+
+import "mojo/services/network/public/interfaces/url_loader.mojom";
+
+// This service allows the mojo shell and content handler to efficiently cache
+// and retrieve mojo applications.
+// TODO(qsr): At the moment, the service cache only handles ETag. It should
+// also handles all the other http cache mechanisms.
+interface ServiceCache {
+
+   // Given a URLResponse, returns a pair of path. |file_path| is a file
+   // containing the body of the response. |cache_dir_path| is a directory that
+   // the applicaton can use to store content. This service guarantee that
+   // |cache_dir_path| will be emptied when |file_path| content changes.
+   GetFile(mojo.URLResponse response) =>
+       (array<uint8>? file_path, array<uint8>? cache_dir_path);
+
+   // Given a URLResponse that is expected to have a zipped body, returns a
+   // pair of path. |extracted_dir_path| is a directory containing the unzipped
+   // body of the response. |cache_dir_path| is a directory that the applicaton
+   // can use to store content. This service guarantee that |cache_dir_path|
+   // will be emptied when |extracted_dir_path| content changes.
+   GetExtractedContent(mojo.URLResponse response) =>
+       (array<uint8>? extracted_dir_path, array<uint8>? cache_dir_path);
+};