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, 0 deletions

diff --git a/Firestore/core/src/firebase/firestore/local/leveldb_transaction.h b/Firestore/core/src/firebase/firestore/local/leveldb_transaction.h
index bcc7c91..56a9a77 100644
--- a/Firestore/core/src/firebase/firestore/local/leveldb_transaction.h
+++ b/Firestore/core/src/firebase/firestore/local/leveldb_transaction.h
@@ -126,6 +126,7 @@ class LevelDbTransaction {
 
   explicit LevelDbTransaction(
       leveldb::DB* db,
+      absl::string_view label,
       const leveldb::ReadOptions& read_options = DefaultReadOptions(),
       const leveldb::WriteOptions& write_options = DefaultWriteOptions());
 
@@ -197,6 +198,7 @@ class LevelDbTransaction {
   leveldb::ReadOptions read_options_;
   leveldb::WriteOptions write_options_;
   int32_t version_;
+  std::string label_;
 };
 
 }  // namespace local