[GRC] UKM Support

services/resource_coordinator/public/interfaces/service_callbacks.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 "components/ukm/public/interfaces/ukm_interface.mojom";
+
+// This class is intended to provide an interface to register mojo interfaces that

[dcheng, 2017/06/23 16:10:35]

mojo interfaces should still obey the 80 character line limit

[matthalp, 2017/06/23 16:36:28]

Done.

+// are not currently accessible to the resource_coordinator service. For example
+// (and the reason for this interface), the UKM mojo interface is accessible to
+// the resource_coordinator service code, as its in //components/, but it's bound
+// within the content_browser service. Therefore, the content_browser service needs
+// to bind to it and pass the message pointer (i.e. message pipe) to the
+// resource_coordinator service. As a result, the ServiceCallbacks interface is
+// strategically called within the content_browser service to pass in the
+// initialized UkmRecorderInterfacePtr to the resource_coordinator service.
+interface ServiceCallbacks {
+  // Checks to see if the resource_coordinator service is already active. Any call to
+  // EnsureUkmRecorderInterface should be enclosed in the callback and called only
+  // when active == true to avoid creating an excessive number of UkmRecorderInterface
+  // mojo connections as the resource_coordinator service will ignore the UkmRecorderInterface
+  // passed into EnsureUkmRecorderInterface if it is already active.
+  IsUkmRecorderInterfaceInitialized() => (bool ukm_recorder_already_initialized);
+
+  SetUkmRecorderInterface(ukm.mojom.UkmRecorderInterface ukm_recorder_interface);
+};