[Sync] Move //sync to //components/sync.

sync/protocol/client_commands.proto

-// Copyright (c) 2012 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 for communication between sync client and server.
-
-// Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
-// any fields in this file.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-option retain_unknown_fields = true;
-
-package sync_pb;
-
-message CustomNudgeDelay {
-  optional int32 datatype_id = 1;  // Datatype id.
-  optional int32 delay_ms = 2;     // Delay in milliseconds.
-};
-
-message ClientCommand {
-  // Time to wait before sending any requests to the server.
-  optional int32 set_sync_poll_interval = 1;  // in seconds
-  optional int32 set_sync_long_poll_interval = 2;  // in seconds
-
-  optional int32 max_commit_batch_size = 3;
-
-  // Number of seconds to delay between a sessions action and sending a commit
-  // message to the server. Can be overridden by |custom_nudge_delays|.
-  optional int32 sessions_commit_delay_seconds = 4;
-
-  // Number of seconds to delay before the throttled client should retry.
-  optional int32 throttle_delay_seconds = 5;
-
-  // Maximum number of local nudges to buffer per-type.
-  optional int32 client_invalidation_hint_buffer_size = 6;
-
-  // Time to wait before issuing a retry GU.
-  optional int32 gu_retry_delay_seconds = 7;
-
-  // A dictionary of custom nudge delays.
-  // Note: if a SESSIONS value is present, this will override
-  // |sessions_commit_delay_seconds|
-  // New in M39.
-  repeated CustomNudgeDelay custom_nudge_delays = 8;
-};