Use an enum in embedded_names as input to JS_GET_NAME.

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

 // 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.
 
 library _foreign_helper;
 
+import 'dart:_js_embedded_names' show JsGetName;
+
 /**
  * Emits a JavaScript code fragment parameterized by arguments.
  *
  * Hash characters `#` in the [codeTemplate] are replaced in left-to-right order
  * with expressions that contain the values of, or evaluate to, the arguments.
  * The number of hash marks must match the number or arguments.  Although
  * declared with arguments [arg0] through [arg2], the form actually has no limit
  * on the number of arguments.
  *
  * The [typeDescription] argument is interpreted as a description of the
@@ skipping 216 matching lines @@
  */
 String JS_FUNCTION_TYPE_OPTIONAL_PARAMETERS_TAG() {}
 
 /**
  * Returns the name used to tag named parameters in function type
  * representations in JavaScript.
  */
 String JS_FUNCTION_TYPE_NAMED_PARAMETERS_TAG() {}
 
 /// Returns the JS name for [name] from the Namer.
-String JS_GET_NAME(String name) {}
+String JS_GET_NAME(JsGetName name) {}
 
 /// Reads an embedded global.
 ///
 /// The [name] should be a constant defined in the `_embedded_names` library.
 JS_EMBEDDED_GLOBAL(String typeDescription, String name) {}
 
 /// Returns the state of a flag that is determined by the state of the compiler
 /// when the program has been analyzed.
 bool JS_GET_FLAG(String name) {}
 
@@ skipping 28 matching lines @@
 }
 
 /**
  * JavaScript string concatenation. Inputs must be Strings.  Corresponds to the
  * HStringConcat SSA instruction and may be constant-folded.
  */
 String JS_STRING_CONCAT(String a, String b) {
   // This body is unused, only here for type analysis.
   return JS('String', '# + #', a, b);
 }