Unbreak frog html tests

lib/dom/templates/html/frog/impl_IDBDatabase.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   _IDBTransactionImpl transaction(storeName_OR_storeNames, String mode) {
     if (mode != 'readonly' && mode != 'readwrite') {
       throw new IllegalArgumentException(mode);
     }
@@ skipping 11 matching lines @@
     var txn = _transaction(storeName_OR_storeNames, mode);
     if (_hasNumericMode(txn)) {
       _transaction_fn = _transaction_numeric_mode;
       txn = _transaction_fn(this, storeName_OR_storeNames, mode);
     } else {
       _transaction_fn = _transaction_string_mode;
     }
     return txn;
   }
 
-  static var _transaction_fn;  // Assigned one of the following:
-
   static _IDBTransactionImpl _transaction_string_mode($CLASSNAME db, stores, mode) {
     return db._transaction(stores, mode);
   }
 
   static _IDBTransactionImpl _transaction_numeric_mode($CLASSNAME db, stores, mode) {
     int intMode;
     if (mode == 'readonly') intMode = IDBTransaction.READ_ONLY;
     if (mode == 'readwrite') intMode = IDBTransaction.READ_WRITE;
     return db._transaction(stores, intMode);
   }
 
   _IDBTransactionImpl _transaction(stores, mode) native 'transaction';
 
   static bool _hasNumericMode(txn) native 'return typeof(txn.mode) === "number"';
 
 $!MEMBERS}
+
+// TODO(sra): This should be a static member of _IDBTransactionImpl but frog
+// can't handle that.  Move it back after frog is completely done.
+var _transaction_fn;  // Assigned one of the static methods.