IndexedDB: Ignore duplicate transaction IDs sent by renderer

content/browser/indexed_db/indexed_db_dispatcher_host.cc

Index: content/browser/indexed_db/indexed_db_dispatcher_host.cc
diff --git a/content/browser/indexed_db/indexed_db_dispatcher_host.cc b/content/browser/indexed_db/indexed_db_dispatcher_host.cc
index abb7a872ec9a458eeff49df67bdafaf173b2f95f..1cbc4b82a4a3163480d4b08173233636535c519f 100644
--- a/content/browser/indexed_db/indexed_db_dispatcher_host.cc
+++ b/content/browser/indexed_db/indexed_db_dispatcher_host.cc
@@ -476,6 +476,12 @@ void IndexedDBDispatcherHost::DatabaseDispatcherHost::OnCreateTransaction(
 
   int64 host_transaction_id = parent_->HostTransactionId(params.transaction_id);
 
+  if (transaction_database_map_.find(host_transaction_id) !=
+      transaction_database_map_.end()) {
+    DLOG(ERROR) << "Duplicate host_transaction_id.";
+    return;
+  }
+
   connection->database()->CreateTransaction(
       host_transaction_id, connection, params.object_store_ids, params.mode);
   transaction_database_map_[host_transaction_id] = params.ipc_database_id;