Drop FSTWriteGroup (#986)

* Drop write group from remote document change buffer

* Unwind some group dependendencies in local store

* Write group dropped from local store

* Drop write group from mutation queue tests

* Drop write group usage from query cache tests

* Drop write groups from remote document cache tests

* Drop write groups from remote document change buffer tests

* Drop write groups and the write group tracker

* Style

* Put the action in transaction

* Merge master, fix test

* Fix some compiler warnings but mostly trigger travis

* Responses to feedback

1 files changed, 2 insertions, 2 deletions

diff --git a/Firestore/Source/Core/FSTSyncEngine.mm b/Firestore/Source/Core/FSTSyncEngine.mm
index d834cc2..673991c 100644
--- a/Firestore/Source/Core/FSTSyncEngine.mm
+++ b/Firestore/Source/Core/FSTSyncEngine.mm
@@ -295,8 +295,8 @@ static const FSTListenSequenceNumber kIrrelevantSequenceNumber = -1;
   [remoteEvent.targetChanges enumerateKeysAndObjectsUsingBlock:^(
                                  FSTBoxedTargetID *_Nonnull targetID,
                                  FSTTargetChange *_Nonnull targetChange, BOOL *_Nonnull stop) {
-    const auto iter = _limboKeysByTarget.find([targetID intValue]);
-    if (iter == _limboKeysByTarget.end()) {
+    const auto iter = self->_limboKeysByTarget.find([targetID intValue]);
+    if (iter == self->_limboKeysByTarget.end()) {
       return;
     }
     const DocumentKey &limboKey = iter->second;