[IndexedDB] Adding txn, value, and key size metrics

content/browser/indexed_db/leveldb/leveldb_transaction.h

Index: content/browser/indexed_db/leveldb/leveldb_transaction.h
diff --git a/content/browser/indexed_db/leveldb/leveldb_transaction.h b/content/browser/indexed_db/leveldb/leveldb_transaction.h
index 19181f0884bf434a140cccd8e3f7b46bb546eee0..bd84377c11664368f7c0d5667bcc493ed0f0a568 100644
--- a/content/browser/indexed_db/leveldb/leveldb_transaction.h
+++ b/content/browser/indexed_db/leveldb/leveldb_transaction.h
@@ -40,6 +40,8 @@ class CONTENT_EXPORT LevelDBTransaction
 
   std::unique_ptr<LevelDBIterator> CreateIterator();
 
+  uint64_t GetTransactionSize() const { return size_; }
+
  protected:
   virtual ~LevelDBTransaction();
   explicit LevelDBTransaction(LevelDBDatabase* db);
@@ -164,6 +166,7 @@ class CONTENT_EXPORT LevelDBTransaction
   const LevelDBComparator* comparator_;
   Comparator data_comparator_;
   DataType data_;
+  uint64_t size_ = 0ull;
   bool finished_ = false;
   std::set<TransactionIterator*> iterators_;