Use an enum in embedded_names as input to JS_GET_NAME.

sdk/lib/_internal/compiler/js_lib/js_names.dart

 // 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.
 
 library dart._js_names;
 
 import 'dart:_js_embedded_names' show
+    JsGetName,
     MANGLED_GLOBAL_NAMES,
     MANGLED_NAMES;
 
 import 'dart:_foreign_helper' show
     JS,
     JS_EMBEDDED_GLOBAL,
     JS_GET_NAME;
 
 import 'dart:_js_helper' show
     JsCache,
@@ skipping 28 matching lines @@
 /// [mangledGlobalNames]).
 final Map<String, String> reflectiveGlobalNames =
     computeReflectiveNames(mangledGlobalNames);
 
 /// [jsMangledNames] is a JavaScript object literal.  The keys are the mangled
 /// names, and the values are the "reflective" names.
 Map<String, String> computeMangledNames(jsMangledNames, bool isGlobal) {
   preserveNames();
   var keys = extractKeys(jsMangledNames);
   var result = <String, String>{};
-  String getterPrefix = JS_GET_NAME('GETTER_PREFIX');
+  String getterPrefix = JS_GET_NAME(JsGetName.GETTER_PREFIX);
   int getterPrefixLength = getterPrefix.length;
-  String setterPrefix = JS_GET_NAME('SETTER_PREFIX');
+  String setterPrefix = JS_GET_NAME(JsGetName.SETTER_PREFIX);
   for (String key in keys) {
     String value = JS('String', '#[#]', jsMangledNames, key);
     result[key] = value;
     if (!isGlobal) {
       if (key.startsWith(getterPrefix)) {
         result['$setterPrefix${key.substring(getterPrefixLength)}'] = '$value=';
       }
     }
   }
   return result;
@@ skipping 37 matching lines @@
   return JsCache.fetch(names, name);
 }
 
 String unmangleAllIdentifiersIfPreservedAnyways(String str) {
   return JS("String",
             r"(#).replace(/[^<,> ]+/g,"
             r"function(m) { return #[m] || m; })",
             str,
             JS_EMBEDDED_GLOBAL('', MANGLED_GLOBAL_NAMES));
 }