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

pkg/analyzer/test/src/summary/linker_test.dart

 // Copyright (c) 2016, 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.
 
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/link.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 217 matching lines @@
   final y;
   const C() : y = x.length;
 }
 const x = [const C()];
 ''');
     testLibrary.libraryCycleForLink.ensureLinked();
     ClassElementForLink classC = testLibrary.getContainedName('C');
     expect(classC.unnamedConstructor.isCycleFree, false);
   }
 
+  void test_createPackageBundle_withPackageUri() {
+    PackageBundle bundle = createPackageBundle(
+        '''
+class B {
+  void f(int i) {}
+}
+class C extends B {
+  f(i) {} // Inferred param type: int
+}
+''',
+        uri: 'package:foo/bar.dart');
+    UnlinkedExecutable cf = bundle.unlinkedUnits[0].classes[1].executables[0];
+    UnlinkedParam cfi = cf.parameters[0];
+    expect(cfi.inferredTypeSlot, isNot(0));
+    EntityRef typeRef =
+        bundle.linkedLibraries[0].units[0].types[cfi.inferredTypeSlot];
+    expect(bundle.unlinkedUnits[0].references[typeRef.reference].name, 'int');
+  }
+
   void test_getContainedName_nonStaticField() {
     createLinker('class C { var f; }');
     LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
     ClassElementForLink_Class c = library.getContainedName('C');
     expect(c.getContainedName('f'), isNot(isUndefined));
   }
 
   void test_getContainedName_nonStaticGetter() {
     createLinker('class C { get g => null; }');
     LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
@@ skipping 641 matching lines @@
     PropertyAccessorElementForLink_Variable j = library.getContainedName('j');
     expect(j.variable.initializer, isNull);
     PropertyAccessorElementForLink_Variable v = library.getContainedName('v');
     expect(v.variable.initializer, isNotNull);
   }
 
   VariableElementForLink _getVariable(ReferenceableElementForLink element) {
     return (element as PropertyAccessorElementForLink_Variable).variable;
   }
 }