Add Mojo interfaces for out-of-process proxy resolver.

net/interfaces/host_resolver_service.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.
+
+// WARNING! Do NOT use this mojom. It is intended as a temporary interface to
+// implement out-of-process proxy resolution. If you wish to use a Mojo DNS
+// service, contact amistry@/sammc@ and net-dev to discuss a permanent Mojo DNS
+// interface.
+
+// Put Mojo definitions into their own namespace to avoid collisions with C++
+// definitions.
+// TODO(amistry): Resolve the conflict between these two sets of definitions.
+module net.interfaces;
+
+// Mirror of net::AddressFamily.
+enum AddressFamily {
+  UNSPECIFIED,
+  IPV4,
+  IPV6,
+};
+
+// Mirror of net::HostResolver::RequestInfo.
+struct HostResolverRequestInfo {
+  string host;
+  uint16 port;
+  AddressFamily address_family;
+  bool is_my_ip_address;
+};
+
+// Mirror of net::IPEndPoint.
+struct IPEndPoint {
+  // IP address as a numeric value from most to least significant byte.
+  // Will be of length 4 for IPv4 addresses and 16 for IPv6.
+  array<uint8> address;
+  uint16 port;
+};
+
+// Mirror of net::AddressList.
+struct AddressList {
+  array<IPEndPoint> addresses;
+};
+
+interface HostResolverService {
+  // Use a HostResolverRequestClient instead of returning a result so we can
+  // cancel in-flight requests by destroying the client.  IPC requests in Mojo
+  // cannot be cancelled directly.
+  // TODO(amistry): Add BoundNetLog.
+  Resolve(HostResolverRequestInfo request_info,
+          HostResolverRequestClient client);
+};
+
+interface HostResolverRequestClient {
+  // |error| is a value in net::Error.
+  ReportResult(int32 error, AddressList? result);
+};