Expand overloaded methods and optional parameters in the html library.

sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart

Index: sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
diff --git a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
index ee98234579ad00979b9b4a21919b86f7cbef5fdf..142b3a98bd5296cf46a16b5475c7e61984482094 100644
--- a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
+++ b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
@@ -249,18 +249,29 @@ class Database extends EventTarget native "IDBDatabase" {
     return $dom_createObjectStore(name, options);
   }
 
-  Transaction transaction(storeName_OR_storeNames, String mode) {
+  Transaction transaction(String storeName, String mode) {
     if (mode != 'readonly' && mode != 'readwrite') {
       throw new ArgumentError(mode);
     }
-
-    // TODO(sra): Ensure storeName_OR_storeNames is a string or List<String>,
-    // and copy to JavaScript array if necessary.
-
     // Try and create a transaction with a string mode.  Browsers that expect a
     // numeric mode tend to convert the string into a number.  This fails
     // silently, resulting in zero ('readonly').
-    return _transaction(storeName_OR_storeNames, mode);
+    return _transaction(storeName, mode);
+  }
+
+  Transaction transactionList(List<String> storeNames, String mode) {
+    if (mode != 'readonly' && mode != 'readwrite') {
+      throw new ArgumentError(mode);
+    }
+    List storeNames_1 = convertDartToNative_StringArray(storeNames);
+    return _transaction(storeNames_1, mode);
+  }
+  
+  Transaction transactionStringList(DomStringList storeNames, String mode) {
+    if (mode != 'readonly' && mode != 'readwrite') {
+      throw new ArgumentError(mode);
+    }
+    return _transaction(storeNames_1, mode);
   }
 
   @JSName('transaction')