Rename elements after sorting.

lib/compiler/implementation/dart_backend/backend.dart

Index: lib/compiler/implementation/dart_backend/backend.dart
diff --git a/lib/compiler/implementation/dart_backend/backend.dart b/lib/compiler/implementation/dart_backend/backend.dart
index e65c90bd669691f7233abee768bbdbf5e6ead6ee..d6549976e77cafbf6f9c663886f8d140036edfd0 100644
--- a/lib/compiler/implementation/dart_backend/backend.dart
+++ b/lib/compiler/implementation/dart_backend/backend.dart
@@ -104,21 +104,10 @@ class DartBackend extends Backend {
     renamePlaceholders(compiler, collector, renames, imports);
 
     // Sort elements.
-    compareElements(e0, e1) {
-      compareBy(x, y, f) => f(x).compareTo(f(y));
-      int result = compareBy(e0, e1, (e) => e.getLibrary().uri.toString());
-      if (result != 0) return result;
-      return compareBy(e0, e1, (e) => e.position().charOffset);
-    }
-
-    final sortedTopLevels = new List<Element>.from(topLevelElements);
-    sortedTopLevels.sort(compareElements);
-
+    final sortedTopLevels = sortElements(topLevelElements);
     final sortedClassMembers = new Map<ClassElement, List<Element>>();
     classMembers.forEach((classElement, members) {
-      final sortedMembers = new List<Element>.from(members);
-      sortedMembers.sort(compareElements);
-      sortedClassMembers[classElement] = sortedMembers;
+      sortedClassMembers[classElement] = sortElements(members);
     });
 
     final unparser = new Unparser.withRenamer((Node node) => renames[node]);
@@ -191,3 +180,16 @@ class ReferencedElementCollector extends AbstractVisitor {
     });
   }
 }
+
+List<Element> sortElements(Collection<Element> elements) {
+  compareElements(e0, e1) {
+    compareBy(x, y, f) => f(x).compareTo(f(y));
+    int result = compareBy(e0, e1, (e) => e.getLibrary().uri.toString());
+    if (result != 0) return result;
+    return compareBy(e0, e1, (e) => e.position().charOffset);
+  }
+
+  final sorted = new List<Element>.from(elements);
+  sorted.sort(compareElements);
+  return sorted;
+}