Modify blink type map to finalize lazily

sdk/lib/indexed_db/dartium/indexed_db_dartium.dart

 library dart.dom.indexed_db;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:nativewrappers';
 import 'dart:_blink' as _blink;
 // 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.
@@ skipping 17 matching lines @@
   static KeyRange createKeyRange_upperBound(
       /*IDBKey*/ bound, [bool open = false]) =>
       KeyRange.upperBound_(bound, open);
 
   static KeyRange createKeyRange_bound(
       /*IDBKey*/ lower, /*IDBKey*/ upper,
       [bool lowerOpen = false, bool upperOpen = false]) =>
       KeyRange.bound_(lower, upper, lowerOpen, upperOpen);
 }
 // FIXME: Can we make this private?
-const indexed_dbBlinkMap = const {
-  'IDBCursor': Cursor,
-  'IDBCursorWithValue': CursorWithValue,
-  'IDBDatabase': Database,
-  'IDBFactory': IdbFactory,
-  'IDBIndex': Index,
-  'IDBKeyRange': KeyRange,
-  'IDBObjectStore': ObjectStore,
-  'IDBOpenDBRequest': OpenDBRequest,
-  'IDBRequest': Request,
-  'IDBTransaction': Transaction,
-  'IDBVersionChangeEvent': VersionChangeEvent,
+final indexed_dbBlinkMap = {
+  'IDBCursor': () => Cursor,
+  'IDBCursorWithValue': () => CursorWithValue,
+  'IDBDatabase': () => Database,
+  'IDBFactory': () => IdbFactory,
+  'IDBIndex': () => Index,
+  'IDBKeyRange': () => KeyRange,
+  'IDBObjectStore': () => ObjectStore,
+  'IDBOpenDBRequest': () => OpenDBRequest,
+  'IDBRequest': () => Request,
+  'IDBTransaction': () => Transaction,
+  'IDBVersionChangeEvent': () => VersionChangeEvent,
 
 };
 // Copyright (c) 2013, 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.
 
 
 @DomName('IDBCursor')
 @Unstable()
 class Cursor extends NativeFieldWrapperClass2 {
@@ skipping 1013 matching lines @@
 
   @DomName('IDBVersionChangeEvent.newVersion')
   @DocsEditable()
   Object get newVersion => _blink.BlinkIDBVersionChangeEvent.$newVersion_Getter(this);
 
   @DomName('IDBVersionChangeEvent.oldVersion')
   @DocsEditable()
   Object get oldVersion => _blink.BlinkIDBVersionChangeEvent.$oldVersion_Getter(this);
 
 }