[mojo talk demo] Convert utility process CheckMediaFile IPC to mojo

chrome/common/extensions/media_parser.mojom

+// Copyright 2016 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.
+
+// Media parsing interface provided by the utility process and exposed by
+// mojo policy control to the chrome browser process.
+
+module extensions.mojom;
+
+import "mojo/common/file.mojom";
+
+interface MediaParser {
+  // Validate the passed media file with sanity checks, and file decoding
+  // for up to |decode_time_ms| wall clock time. Return |success| true if
+  // |file| appears to be a well-formed media file. Note: it is still not
+  // safe to decode the file in the browser process based on the returned
+  // |success|.
+  CheckMediaFile(int64 decode_time_ms, mojo.common.mojom.File file) 
+      => (bool success);
+};