NOCOMMIT prototype: GRC service plumbing and process priority

services/resource_coordinator/public/interfaces/coordination_unit.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.
+
+module resource_coordinator.mojom;
+
+import "events.mojom";
+
+enum IDType {
+        NONE,
+        WEBCONTENTS,
+        FRAME,
+        NAVIGATION,
+        PROCESS
+};
+
+struct CoordinationUnitID {
+  IDType type;
+  string id;
+};
+
+struct Policy {
+  bool use_background_priority;
+};
+
+interface PolicyCallback {
+  SetPolicy(Policy policy);
+};
+
+interface CoordinationUnit {
+  SendEvent(Event event);
+
+  GetID() => (CoordinationUnitID id);
+  Duplicate(CoordinationUnit& request);
+  AddChild(CoordinationUnitID child_id);

[Ken Rockot(use gerrit already), 2017/03/15 22:51:55]

I haven't fully understood the design here, so I might be spouting stupid
nonsense. Is it possible to avoid having this notion of a "CoordinationUnitID"
by making the hierarchy a permanent implicit property of CoordinationUnits? i.e.
could we somehow build this system with the interface looking more like:

interface CoordinationUnit {
  SendEvent(Event event);
  Duplicate(CoordinationUnit& request);
  AddChild(CoordinationUnit& request);
  SetPolicyCallback(PolicyCallback callback);
};

?

[oystein (OOO til 10th of July), 2017/03/15 23:12:24]

I'd love to get rid of CoordinationUnitID, but unfortunately since a
CoordinationUnit can have multiple parents (it's a DAG rather than a tree), I
need to be able to form a connection without creating a new node at the same
time :/. I was trying to see if there's some kind of Mojo binding ID or
something I could use instead but didn't have much luck.

+  SetPolicyCallback(PolicyCallback callback);
+};