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

sync/internal_api/public/base/node_ordinal.h

-// Copyright 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.
-
-#ifndef SYNC_INTERNAL_API_PUBLIC_BASE_NODE_ORDINAL_H_
-#define SYNC_INTERNAL_API_PUBLIC_BASE_NODE_ORDINAL_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include "sync/base/sync_export.h"
-#include "sync/internal_api/public/base/ordinal.h"
-
-namespace syncer {
-
-// A NodeOrdinal is an Ordinal whose internal value comes from the
-// ordinal_in_parent field of SyncEntity (see sync.proto).  It uses
-// the entire uint8_t range for backwards compatibility with the old
-// int64_t-based positioning.
-
-struct NodeOrdinalTraits {
-  static const uint8_t kZeroDigit = 0;
-  static const uint8_t kMaxDigit = UINT8_MAX;
-  static const size_t kMinLength = 8;
-};
-
-typedef Ordinal<NodeOrdinalTraits> NodeOrdinal;
-
-static_assert(static_cast<char>(NodeOrdinal::kZeroDigit) == '\x00',
-              "NodeOrdinal has incorrect zero digit");
-static_assert(static_cast<char>(NodeOrdinal::kOneDigit) == '\x01',
-              "NodeOrdinal has incorrect one digit");
-static_assert(static_cast<char>(NodeOrdinal::kMidDigit) == '\x80',
-              "NodeOrdinal has incorrect mid digit");
-static_assert(static_cast<char>(NodeOrdinal::kMaxDigit) == '\xff',
-              "NodeOrdinal has incorrect max digit");
-static_assert(NodeOrdinal::kMidDigitValue == 128,
-              "NodeOrdinal has incorrect mid digit value");
-static_assert(NodeOrdinal::kMaxDigitValue == 255,
-              "NodeOrdinal has incorrect max digit value");
-static_assert(NodeOrdinal::kRadix == 256,
-              "NodeOrdinal has incorrect radix");
-
-// Converts an int64_t position (usually from the position_in_parent
-// field of SyncEntity) to a NodeOrdinal.  This transformation
-// preserves the ordering relation: a < b under integer ordering if
-// and only if Int64ToNodeOrdinal(a) < Int64ToNodeOrdinal(b).
-SYNC_EXPORT NodeOrdinal Int64ToNodeOrdinal(int64_t x);
-
-// The inverse of Int64ToNodeOrdinal.  This conversion is, in general,
-// lossy: NodeOrdinals can have arbitrary fidelity, while numeric
-// positions contain only 64 bits of information (in fact, this is the
-// reason we've moved away from them).
-SYNC_EXPORT int64_t NodeOrdinalToInt64(const NodeOrdinal& ordinal);
-
-}  // namespace syncer
-
-#endif  // SYNC_INTERNAL_API_PUBLIC_BASE_NODE_ORDINAL_H_