Translate package URIs to resource URIs for diagnostics.

tests/compiler/dart2js/show_package_warnings_test.dart

 // Copyright (c) 2014, 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.
 
 // Test that the '--show-package-warnings' option works as intended.
 
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 
 import 'memory_compiler.dart';
@@ skipping 51 matching lines @@
   } else {
     compiler.librariesToAnalyzeWhenRun = entryPoints;
   }
   asyncTest(() => compiler.run(mainUri).then((_) {
     print('==================================================================');
     print('test: $entryPoints showPackageWarnings=$showPackageWarnings');
     Expect.equals(0, collector.errors.length,
                   'Unexpected errors: ${collector.errors}');
     Expect.equals(warnings, collector.warnings.length,
                   'Unexpected warnings: ${collector.warnings}');
+    checkUriSchemes(collector.warnings);
     Expect.equals(hints, collector.hints.length,
                   'Unexpected hints: ${collector.hints}');
+    checkUriSchemes(collector.hints);
     Expect.equals(infos, collector.infos.length,
                   'Unexpected infos: ${collector.infos}');
+    checkUriSchemes(collector.infos);
     print('==================================================================');
   }));
 }
 
+void checkUriSchemes(Iterable<DiagnosticMessage> messages) {
+  for (DiagnosticMessage message in messages) {
+    if (message.uri != null) {
+      Expect.notEquals('package', message.uri.scheme,
+          "Unexpected package uri `${message.uri}` in message: $message");
+    }
+  }
+}
+
 void main() {
   test([Uri.parse('memory:main.dart')],
        showPackageWarnings: true,
        // From error.dart, package:pkg_error1 and package:pkg_error2:
        warnings: 3, hints: 3, infos: 3);
   test([Uri.parse('memory:main.dart')],
        showPackageWarnings: false,
        // From error.dart only:
        warnings: 1, hints: 1 + 2 /* from summary */, infos: 1);
   test([Uri.parse('package:pkg_error1/pkg_error1.dart')],
        showPackageWarnings: true,
        // From package:pkg_error1 and package:pkg_error2:
        warnings: 2, hints: 2, infos: 2);
   test([Uri.parse('package:pkg_error1/pkg_error1.dart')],
        showPackageWarnings: false,
        // From package:pkg_error1/pkg_error1.dart only:
        warnings: 1, hints: 1 + 1 /* from summary */, infos: 1);
   test([Uri.parse('package:pkg_noerror/pkg_noerror.dart')],
        showPackageWarnings: true,
        // From package:pkg_error1 and package:pkg_error2:
        warnings: 2, hints: 2, infos: 2);
   test([Uri.parse('package:pkg_noerror/pkg_noerror.dart')],
        showPackageWarnings: false,
        hints: 2 /* from summary */);
 }