Add PrinterSpecifics to the sync protos.

components/sync/protocol/printer_specifics.proto

+// 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.
+//
+// Sync protocol datatype extension for printer data.
+
+// Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
+// any fields in this file.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package sync_pb;
+
+// Properties of PPDs associated with printers.
+message PrinterPPDData {
+  optional int32 id = 1 [default = 0];

[Nicolas Zea, 2016/09/07 00:18:04]

Please add descriptions for each of these fields you're introducing. In
particular what format they're in, and what they're used for.

[skau, 2016/09/09 19:02:15]

Done.

+  optional string file_name = 2;
+  optional int64 version_number = 3;
+  optional bool from_quirks_server = 4 [default = false];
+}
+
+message PrinterSpecifics {
+  optional string id = 1;
+  optional string display_name = 2;
+  optional string description = 3;
+  optional string manufacturer = 4;
+  optional string model = 5;
+  optional string uri = 6;
+  optional string uuid = 7;
+  optional PrinterPPDData ppd = 8;
+}