Implement a bag of chips for sync.

sync/engine/syncer_proto_util.h

 // 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.
 
 #ifndef SYNC_ENGINE_SYNCER_PROTO_UTIL_H_
 #define SYNC_ENGINE_SYNCER_PROTO_UTIL_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 56 matching lines @@
                                      std::string* proto_bytes);
 
   // Extract the name field from a sync entity.
   static const std::string& NameFromSyncEntity(
       const sync_pb::SyncEntity& entry);
 
   // Extract the name field from a commit entry response.
   static const std::string& NameFromCommitEntryResponse(
       const sync_pb::CommitResponse_EntryResponse& entry);
 
+  // Persist the bag of chips if it is present in the response.
+  static void PersistBagOfChips(
+      syncable::Directory* dir,
+      const sync_pb::ClientToServerResponse& response);
+
   // EntitySpecifics is used as a filter for the GetUpdates message to tell
   // the server which datatypes to send back.  This adds a datatype so that
   // it's included in the filter.
   static void AddToEntitySpecificDatatypesFilter(ModelType datatype,
       sync_pb::EntitySpecifics* filter);
 
   // Get a debug string representation of the client to server response.
   static std::string ClientToServerResponseDebugString(
       const sync_pb::ClientToServerResponse& response);
 
   // Get update contents as a string. Intended for logging, and intended
   // to have a smaller footprint than the protobuf's built-in pretty printer.
   static std::string SyncEntityDebugString(const sync_pb::SyncEntity& entry);
 
   // Pull the birthday from the dir and put it into the msg.
   static void AddRequestBirthday(syncable::Directory* dir,
                                  sync_pb::ClientToServerMessage* msg);
 
+  // Pull the bag of chips from the dir and put it into the msg.
+  static void AddBagOfChips(syncable::Directory* dir,
+                            sync_pb::ClientToServerMessage* msg);
+
+
   // Set the protocol version field in the outgoing message.
   static void SetProtocolVersion(sync_pb::ClientToServerMessage* msg);
 
  private:
   SyncerProtoUtil() {}
 
   // Helper functions for PostClientToServerMessage.
 
   // Verifies the store birthday, alerting/resetting as appropriate if there's a
   // mismatch. Return false if the syncer should be stuck.
@@ skipping 28 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(SyncerProtoUtilTest, VerifyResponseBirthday);
   FRIEND_TEST_ALL_PREFIXES(SyncerProtoUtilTest, HandleThrottlingNoDatatypes);
   FRIEND_TEST_ALL_PREFIXES(SyncerProtoUtilTest, HandleThrottlingWithDatatypes);
 
   DISALLOW_COPY_AND_ASSIGN(SyncerProtoUtil);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_SYNCER_PROTO_UTIL_H_