sync: Expose BuildCommitItem helper function

Refactor the part of BuildCommitCommand responsible for serializing a
single syncable::Entry into a commit message protobuf into a separate
function.  This will be useful when we try to refactor the sync engine
to be more model-type aware.

BUG=278484

Review URL: https://chromiumcodereview.appspot.com/22859066

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@219670 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 7 insertions, 5 deletions

diff --git a/sync/syncable/syncable_base_transaction.cc b/sync/syncable/syncable_base_transaction.cc
index d068bb9..a1d3e85 100644
--- a/sync/syncable/syncable_base_transaction.cc
+++ b/sync/syncable/syncable_base_transaction.cc
@@ -10,12 +10,13 @@
 namespace syncer {
 namespace syncable {
 
-Directory* BaseTransaction::directory() const {
-  return directory_;
+// static
+Id BaseTransaction::root_id() {
+  return Id();
 }
 
-Id BaseTransaction::root_id() const {
-  return Id();
+Directory* BaseTransaction::directory() const {
+  return directory_;
 }
 
 void BaseTransaction::Lock() {
diff --git a/sync/syncable/syncable_base_transaction.h b/sync/syncable/syncable_base_transaction.h
index e15a38b..58c7bfa 100644
--- a/sync/syncable/syncable_base_transaction.h
+++ b/sync/syncable/syncable_base_transaction.h
@@ -33,8 +33,9 @@ std::string WriterTagToString(WriterTag writer_tag);
 
 class SYNC_EXPORT BaseTransaction {
  public:
+  static Id root_id();
+
   Directory* directory() const;
-  Id root_id() const;
 
   virtual ~BaseTransaction();