Convert utility process extension Unpacker IPC to mojo

extensions/common/extension_unpacker.mojom

+// Copyright 2017 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.
+
+// Secure chrome extension unpacker service provided by the utility process
+// and exposed by mojo policy to the chrome browser process.
+
+module extensions.mojom;
+
+import "mojo/common/file_path.mojom";
+import "mojo/common/string16.mojom";
+import "mojo/common/values.mojom";
+
+interface ExtensionUnpacker {
+  // Unzip |file| into the directory |path|.
+  Unzip(mojo.common.mojom.FilePath file,
+        mojo.common.mojom.FilePath path) => (bool success);
+
+  // Unpack, validate, and sanitize the extension in directory |path|, and
+  // return the parsed manifest.json file in |manifest|.
+  // If unpacking fails, |error| is a user-displayable explanation of what
+  // went wrong.
+  Unpack(mojo.common.mojom.FilePath path,
+         string extension_id,
+         int32 location,

[dcheng, 2017/02/28 06:12:49]

Document location and creation_flags. Location should probably just be plumbed
through as an enum. creation_flags looks like a bitmask, but let's have a
breadcrumb that points at the C++ definitions for the enum flags.

[Noel Gordon, 2017/03/06 13:12:03]

OK, added complete mojo enum type traits for the location.
The C++ definitions are now all in enum traits files (which is a bit more than a
breadcrumb).  What is the breadcrumb you're asking for, and what additional file
or files need it now we have mojo traits?

[dcheng, 2017/03/07 09:45:13]

I think just have a pointer to what the underlying C++ enum is for
creation_flags (I believe it's
https://cs.chromium.org/chromium/src/extensions/common/extension.h?rcl=f763e1...)

[Noel Gordon, 2017/03/08 13:44:26]

Added a creation_flags breadcrumb.

(I believe it's
Thank you and yeap, I think that's the one also.

+         int32 creation_flags)
+      => (mojo.common.mojom.String16 error,
+          mojo.common.mojom.DictionaryValue manifest);
+};