IndexedDB: Clean up boilerplate when throwing TransactionInactiveError

third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h

Index: third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
diff --git a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
index f24644ae8a8cc8c69d37537b2c495bb12ff7ee10..7bc8996bfcff52188d6b9e1f4545e182ece436ab 100644
--- a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
+++ b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
@@ -141,6 +141,10 @@ class MODULES_EXPORT IDBTransaction final
     return old_database_metadata_.max_object_store_id;
   }
 
+  // Returns a detailed message to use when throwing TransactionInactiveError,
+  // depending on whether the transaction is just inactive or has finished.
+  const char* InactiveErrorMessage() const;
+
  protected:
   // EventTarget
   DispatchEventResult DispatchEventInternal(Event*) override;