Fix error message for library name mismatch.

sdk/lib/_internal/compiler/implementation/elements/modelx.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 elements.modelx;
 
 import 'dart:uri';
 
 import 'elements.dart';
 import '../../compiler.dart' as api;
@@ skipping 489 matching lines @@
     if (partTag != null) {
       listener.reportMessage(
           listener.spanFromSpannable(tag),
           MessageKind.DUPLICATED_PART_OF.error(),
           api.Diagnostic.WARNING);
       return;
     }
     partTag = tag;
     LibraryName libraryTag = getLibrary().libraryTag;
     if (libraryTag != null) {
-      String expectedName = tag.name.toString();
-      String actualName = libraryTag.name.toString();
+      String actualName = tag.name.toString();
+      String expectedName = libraryTag.name.toString();
       if (expectedName != actualName) {
         listener.reportMessage(
             listener.spanFromSpannable(tag.name),
             MessageKind.LIBRARY_NAME_MISMATCH.error([expectedName]),
             api.Diagnostic.WARNING);
       }
     }
   }
 
   bool get hasMembers => !localMembers.isEmpty;
@@ skipping 1445 matching lines @@
 
   MetadataAnnotation ensureResolved(Compiler compiler) {
     if (resolutionState == STATE_NOT_STARTED) {
       compiler.resolver.resolveMetadataAnnotation(this);
     }
     return this;
   }
 
   String toString() => 'MetadataAnnotation($value, $resolutionState)';
 }