Allow constant static fields to overwrite defaults

lib/src/compiler/code_generator.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
@@ skipping 3387 matching lines @@
 
     _loader.startCheckingReferences();
     JS.Expression jsInit = _visitInitializer(field);
     bool isLoaded = _loader.finishCheckingReferences();
 
     bool eagerInit =
         isLoaded && (field.isConst || _constField.isFieldInitConstant(field));
 
     var fieldName = field.name.name;
     if (eagerInit &&
         !JS.invalidStaticFieldName(fieldName) &&

[Jennifer Messerly, 2016/06/15 20:28:53]

So this check above was supposed to handle the invalid field name. Can we add
"name" to that?

[stanm, 2016/06/15 20:51:05]

Done.

         !staticFieldOverrides.contains(element)) {
       return annotate(
-          js.statement('#.# = #;', [
+          js.statement('Object.defineProperty(#, #, { value: # });', [

[stanm, 2016/06/15 20:51:40]

Reverted in second patch set.

             _emitTopLevelName(classElem),
             _emitMemberName(fieldName, isStatic: true),
             jsInit
           ]),
           field,
           field.element);
     }
 
     // This means it should be treated as a lazy field.
     // TODO(jmesserly): we're throwing away the initializer expression,
@@ skipping 1710 matching lines @@
 }
 
 bool isLibraryPrefix(Expression node) =>
     node is SimpleIdentifier && node.staticElement is PrefixElement;
 
 LibraryElement _getLibrary(AnalysisContext c, String uri) =>
     c.computeLibraryElement(c.sourceFactory.forUri(uri));
 
 bool _isDartRuntime(LibraryElement l) =>
     l.isInSdk && l.source.uri.toString() == 'dart:_runtime';