[Sync] Don't commit items with predecessors/parents in conflict.

chrome/browser/sync/engine/get_commit_ids_command.h

Index: chrome/browser/sync/engine/get_commit_ids_command.h
diff --git a/chrome/browser/sync/engine/get_commit_ids_command.h b/chrome/browser/sync/engine/get_commit_ids_command.h
index b7286711860832d58bb8713f958ed8a5a59de761..7b4e8ef9660ba801ad18e82efd08071503a40d4c 100644
--- a/chrome/browser/sync/engine/get_commit_ids_command.h
+++ b/chrome/browser/sync/engine/get_commit_ids_command.h
@@ -129,18 +129,34 @@ class GetCommitIdsCommand : public SyncerCommand {
   // OrderedCommitSet helpers for adding predecessors in order.
   // TODO(ncarter): Refactor these so that the |result| parameter goes away,
   // and AddItem doesn't need to consider two OrderedCommitSets.
+
+  // Adds |item| to |result| if it's ready for committing and was not already
+  // present. If |item| was added, returns true. If item already existed,
+  // returns false. If item was not ready for commit, clears |result| and

[akalin, 2011/12/15 01:58:20]

Is there a reason for the 'clear results' action on false?  It seems like the
caller of this function eventually discards the OrderedCommitSet anyway.

+  // returns false.
   bool AddItem(syncable::Entry* item,
                syncable::ModelTypeSet throttled_types,
                sessions::OrderedCommitSet* result);
+  // Adds item and all it's unsynced predecessors to |result| if all that are
+  // unsynced are ready for commit. If either item or any of it's predecessors
+  // are unsynced but not ready for commit, clears |result|.
+  // Return values:
+  //   True: if unsynced items were added to |result| and processing of this set
+  //         should continue.
+  //   False: if processing of the set should not continue, either because not
+  //          all unsynced items were ready for commit or the items are already
+  //          present in |result|.
   bool AddItemThenPredecessors(syncable::BaseTransaction* trans,
                                syncable::ModelTypeSet throttled_types,
                                syncable::Entry* item,
-                               syncable::IndexedBitField inclusion_filter,
                                sessions::OrderedCommitSet* result);
+  // Appends all unsynced predecessors of |item|, followed by |item| iteself,

[akalin, 2011/12/14 03:39:52]

iteself -> itself

+  // to |ordered_commit_set_|, iff item and all its unsynced predecessors
+  // are ready for commit. If |item| or any of it's unsynced predecessors
+  // are unready for commit, does not modify |ordered_commit_set_|.

[akalin, 2011/12/14 03:39:52]

unready -> not ready

   void AddPredecessorsThenItem(syncable::BaseTransaction* trans,
                                syncable::ModelTypeSet throttled_types,
                                syncable::Entry* item,
-                               syncable::IndexedBitField inclusion_filter,
                                const ModelSafeRoutingInfo& routes);
 
   bool IsCommitBatchFull();