Allow constant static fields to overwrite defaults

lib/src/compiler/code_generator.dart

Index: lib/src/compiler/code_generator.dart
diff --git a/lib/src/compiler/code_generator.dart b/lib/src/compiler/code_generator.dart
index ec33413eba317246a9ee699c4d550d9154f0f54c..3f3722f4ff7f1b5315472b82952cbde6ee5eb5a0 100644
--- a/lib/src/compiler/code_generator.dart
+++ b/lib/src/compiler/code_generator.dart
@@ -3408,7 +3408,7 @@ class CodeGenerator extends GeneralizingAstVisitor
         !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