3 files changed, 34 insertions, 9 deletions
diff --git a/sync/protocol/sync.proto b/sync/protocol/sync.proto
index 6aea1d0..0dafdc4 100644
--- a/sync/protocol/sync.proto
+++ b/sync/protocol/sync.proto
@@ -38,6 +38,7 @@ import "sync_enums.proto";
 import "synced_notification_specifics.proto";
 import "theme_specifics.proto";
 import "typed_url_specifics.proto";
+import "unique_position.proto";
 
 // Used for inspecting how long we spent performing operations in different
 // backends. All times must be in millis.
@@ -332,14 +333,6 @@ message SyncEntity {
 
   // This is the fourth attempt at positioning.
   //
-  // Unique positions are unique per-item, since they are guaranteed to end with
-  // a fixed-length suffix that is unique per-item.  The position string may not
-  // end with a '\0' byte.
-  //
-  // Prior to the suffix is a series of arbitrary bytes of arbitrary length.
-  // Items under the same parent are positioned relative to each other by a
-  // lexicographic comparison of their UniquePosition values.
-  //
   // This field is present in both GetUpdatesResponse and CommitMessage, if the
   // item's type requires it and the client that wrote the item supports it (M26
   // or higher).  Clients must also be prepared to handle updates from clients
@@ -349,7 +342,10 @@ message SyncEntity {
   // This field will not be set for items whose type ignores positioning.
   // Clients should not attempt to read this field on the receipt of an item of
   // a type that ignores positioning.
-  optional bytes unique_position = 25;
+  //
+  // Refer to its definition in unique_position.proto for more information about
+  // its internal representation.
+  optional UniquePosition unique_position = 25;
 };
 
 // This message contains diagnostic information used to correlate
diff --git a/sync/protocol/sync_proto.gyp b/sync/protocol/sync_proto.gyp
index 4745044..31d717f 100644
--- a/sync/protocol/sync_proto.gyp
+++ b/sync/protocol/sync_proto.gyp
@@ -37,6 +37,7 @@
         'test.proto',
         'theme_specifics.proto',
         'typed_url_specifics.proto',
+        'unique_position.proto',
       ],
       'variables': {
         'proto_out_dir': 'sync/protocol',
diff --git a/sync/protocol/unique_position.proto b/sync/protocol/unique_position.proto
new file mode 100644
index 0000000..c074312
--- /dev/null
+++ b/sync/protocol/unique_position.proto
@@ -0,0 +1,28 @@
+// 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.
+//
+// Protobuf representation of the UniquePosition class.
+
+// 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;
+
+// A UniquePosition is a string of bytes.
+//
+// Unique positions are unique per-item, since they are guaranteed to end with a
+// fixed-length suffix that is unique per-item.  The position string may not end
+// with a '\0' byte.
+//
+// Prior to the suffix is a series of arbitrary bytes of arbitrary length.
+// Items under the same parent are positioned relative to each other by a
+// lexicographic comparison of their UniquePosition values.
+message UniquePosition {
+  optional bytes value = 1;
+}