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

content/browser/indexed_db/indexed_db_fake_backing_store.cc

Index: content/browser/indexed_db/indexed_db_fake_backing_store.cc
diff --git a/content/browser/indexed_db/indexed_db_fake_backing_store.cc b/content/browser/indexed_db/indexed_db_fake_backing_store.cc
index d89073d9e51f4cbd1b5f8c03352ee047bd89d230..2eaea3eae9e2af2a038f4dc9b84fe025c6b7ff83 100644
--- a/content/browser/indexed_db/indexed_db_fake_backing_store.cc
+++ b/content/browser/indexed_db/indexed_db_fake_backing_store.cc
@@ -224,6 +224,9 @@ leveldb::Status IndexedDBFakeBackingStore::FakeTransaction::CommitPhaseOne(
 leveldb::Status IndexedDBFakeBackingStore::FakeTransaction::CommitPhaseTwo() {
   return result_;
 }
+uint64_t IndexedDBFakeBackingStore::FakeTransaction::GetTransactionSize() {
+  return 0;
+}
 void IndexedDBFakeBackingStore::FakeTransaction::Rollback() {}
 
 }  // namespace content