dart2js: Fix encoding of field names in csp mode.

pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart

Index: pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
index d3b8ffbe01ab2482191425a8885c31d57afee214..552fd27b1bf63c42d822ef92512234d670d4ca74 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
@@ -1026,9 +1026,8 @@ class OldEmitter implements Emitter {
     bool hasIsolateSupport = compiler.hasIsolateSupport;
     jsAst.Node fieldNamesArray;
     if (hasIsolateSupport) {
-      fieldNamesArray = js.concatenateStrings(
-          js.joinLiterals(fields, js.stringPart(",")),
-          addQuotes: true);
+      fieldNamesArray =
+          new jsAst.ArrayInitializer(fields.map(js.quoteName).toList());
     } else {
       fieldNamesArray = new jsAst.LiteralNull();
     }