Fix resolveRelativeUri() to handle correctly empty contained Uri(s).

pkg/analyzer/lib/src/generated/utilities_dart.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.
 
 library analyzer.src.generated.utilities_dart;
 
 import 'package:analyzer/dart/ast/ast.dart' show AnnotatedNode, Comment;
 import 'package:analyzer/dart/ast/token.dart' show Token;
 import 'package:analyzer/src/dart/element/element.dart' show ElementImpl;
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/util/fast_uri.dart';
 
 /**
  * Resolve the [containedUri] against [baseUri] using Dart rules.
  *
  * This function behaves similarly to [Uri.resolveUri], except that it properly
  * handles situations like the following:
  *
  *     resolveRelativeUri(dart:core, bool.dart) -> dart:core/bool.dart
  *     resolveRelativeUri(package:a/b.dart, ../c.dart) -> package:a/c.dart
  */
 Uri resolveRelativeUri(Uri baseUri, Uri containedUri) {
   if (containedUri.isAbsolute) {
     return containedUri;
   }
   Uri origBaseUri = baseUri;
   try {
-    bool isOpaque = baseUri.isAbsolute && !baseUri.path.startsWith('/');
-    if (isOpaque) {
-      String scheme = baseUri.scheme;
+    String scheme = baseUri.scheme;
+    if (scheme == DartUriResolver.DART_SCHEME) {
       String part = baseUri.path;
-      if (scheme == DartUriResolver.DART_SCHEME && part.indexOf('/') < 0) {
-        part = "$part/$part.dart";
+      if (part.indexOf('/') < 0) {
+        baseUri = FastUri.parse('$scheme:$part/$part.dart');
       }
-      baseUri = FastUri.parse("$scheme:/$part");
     }
-    Uri result = baseUri.resolveUri(containedUri);
-    if (isOpaque) {
-      result =
-          FastUri.parse("${result.scheme}:${result.path.substring(1)}");
-    }
-    return result;
+    return baseUri.resolveUri(containedUri);
   } catch (exception, stackTrace) {
     throw new AnalysisException(
         "Could not resolve URI ($containedUri) relative to source ($origBaseUri)",
         new CaughtException(exception, stackTrace));
   }
 }
 
 /**
  * If the given [node] has a documentation comment, remember its content
  * and range into the given [element].
@@ skipping 57 matching lines @@
   final bool isOptional;
 
   /**
    * Initialize a newly created kind with the given state.
    *
    * @param isOptional `true` if this is an optional parameter
    */
   const ParameterKind(String name, int ordinal, this.isOptional)
       : super(name, ordinal);
 }