[Sync] Move ChangeRecord into its own file (change_record.{h,cc})

chrome/browser/sync/internal_api/change_reorder_buffer.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/sync/internal_api/change_reorder_buffer.h"
 
 #include <limits>
 #include <queue>
 #include <set>
 #include <utility>  // for pair<>
@@ skipping 103 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(Traversal);
 };
 
 ChangeReorderBuffer::ChangeReorderBuffer() {
 }
 
 ChangeReorderBuffer::~ChangeReorderBuffer() {
 }
 
-void ChangeReorderBuffer::GetAllChangesInTreeOrder(
-    const BaseTransaction* sync_trans,
-    vector<ChangeRecord>* changelist) {
+ImmutableChangeRecordList ChangeReorderBuffer::GetAllChangesInTreeOrder(
+    const BaseTransaction* sync_trans) {
   syncable::BaseTransaction* trans = sync_trans->GetWrappedTrans();
 
   // Step 1: Iterate through the operations, doing three things:
   // (a) Push deleted items straight into the |changelist|.
   // (b) Construct a traversal spanning all non-deleted items.
   // (c) Construct a set of all parent nodes of any position changes.
   set<int64> parents_of_position_changes;
   Traversal traversal;
 
+  ChangeRecordList changelist;
+
   OperationMap::const_iterator i;
   for (i = operations_.begin(); i != operations_.end(); ++i) {
     if (i->second == OP_DELETE) {
       ChangeRecord record;
       record.id = i->first;
       record.action = ChangeRecord::ACTION_DELETE;
       if (specifics_.find(record.id) != specifics_.end())
         record.specifics = specifics_[record.id];
       if (extra_data_.find(record.id) != extra_data_.end())
         record.extra = extra_data_[record.id];
-      changelist->push_back(record);
+      changelist.push_back(record);
     } else {
       traversal.ExpandToInclude(trans, i->first);
       if (i->second == OP_ADD ||
           i->second == OP_UPDATE_POSITION_AND_PROPERTIES) {
         ReadNode node(sync_trans);
         CHECK(node.InitByIdLookup(i->first));
 
         // We only care about parents of entry's with position-sensitive models.
         if (syncable::ShouldMaintainPosition(
                 node.GetEntry()->GetModelType())) {
@@ skipping 17 matching lines @@
       ChangeRecord record;
       record.id = next;
       if (i->second == OP_ADD)
         record.action = ChangeRecord::ACTION_ADD;
       else
         record.action = ChangeRecord::ACTION_UPDATE;
       if (specifics_.find(record.id) != specifics_.end())
         record.specifics = specifics_[record.id];
       if (extra_data_.find(record.id) != extra_data_.end())
         record.extra = extra_data_[record.id];
-      changelist->push_back(record);
+      changelist.push_back(record);
     }
 
     // Now add the children of |next| to |to_visit|.
     if (parents_of_position_changes.find(next) ==
         parents_of_position_changes.end()) {
         // No order changes on this parent -- traverse only the nodes listed
         // in the traversal (and not in sibling order).
         Traversal::LinkSet::const_iterator j = traversal.begin_children(next);
         Traversal::LinkSet::const_iterator end = traversal.end_children(next);
         for (; j != end; ++j) {
@@ skipping 13 matching lines @@
         to_visit.push(handle);
         // If there is no operation on this child node, record it as as an
         // update, so that the listener gets notified of all nodes in the new
         // ordering.
         if (operations_.find(handle) == operations_.end())
           operations_[handle] = OP_UPDATE_POSITION_AND_PROPERTIES;
         id = child.Get(syncable::NEXT_ID);
       }
     }
   }
+
+  return ImmutableChangeRecordList(&changelist);
 }
 
 }  // namespace sync_api