Patch refactoring.

lib/compiler/implementation/js_backend/namer.dart

Index: lib/compiler/implementation/js_backend/namer.dart
diff --git a/lib/compiler/implementation/js_backend/namer.dart b/lib/compiler/implementation/js_backend/namer.dart
index 80518d3fa748eda142cbac1c9f7cde1f76fddff5..9c89e19d0a0ab8d103e2a21ea206b7b8b00264b1 100644
--- a/lib/compiler/implementation/js_backend/namer.dart
+++ b/lib/compiler/implementation/js_backend/namer.dart
@@ -18,6 +18,12 @@ class Namer {
     return _jsReserved;
   }
 
+  /**
+   * Map from top-level or static elements to their unique identifiers provided
+   * by [getName].
+   *
+   * Invariant: Keys must be declaration elements.
+   */
   final Map<Element, String> globals;
   final Map<String, int> usedGlobals;
   final Map<String, LibraryElement> shortPrivateNameOwners;
@@ -113,7 +119,7 @@ class Namer {
     } else {
       StringBuffer suffix = new StringBuffer();
       signature.forEachOptionalParameter((Element element) {
-        String jsName = JsNames.getValid(element.name.slowToString());        
+        String jsName = JsNames.getValid(element.name.slowToString());
         suffix.add('\$$jsName');
       });
       return '$methodName$suffix';
@@ -244,6 +250,9 @@ class Namer {
                                node: element.parseNode(compiler));
       }
     } else {
+      // Use declaration element to ensure invariant on [globals].
+      element = element.declaration;
+
       // Dealing with a top-level or static element.
       String cached = globals[element];
       if (cached !== null) return cached;