Tighten up dependencies in the task model.

pkg/analyzer/test/src/task/dart_test.dart

Index: pkg/analyzer/test/src/task/dart_test.dart
diff --git a/pkg/analyzer/test/src/task/dart_test.dart b/pkg/analyzer/test/src/task/dart_test.dart
index e8b58134213a12e130e2a0b210daad715854d874..857f352d2326da25180d46f1da9955d790a5f34d 100644
--- a/pkg/analyzer/test/src/task/dart_test.dart
+++ b/pkg/analyzer/test/src/task/dart_test.dart
@@ -2338,7 +2338,7 @@ class C extends A {}
     }
   }
 
-  test_perform_deep() {
+  test_perform_external() {
     Source sourceA = newSource('/a.dart', '''
 library a;
 import 'b.dart';
@@ -2346,18 +2346,10 @@ class A extends B {}
 ''');
     newSource('/b.dart', '''
 library b;
-import 'c.dart';
-part 'b2.dart';
-class B extends B2 {}
-''');
-    newSource('/b2.dart', '''
-part of b;
-class B2 extends C {}
-''');
-    newSource('/c.dart', '''
-library c;
-class C {}
+class B {}
 ''');
+    // The reference A to B should be resolved, but there's no requirement that
+    // the full class hierarchy be resolved.
     computeResult(sourceA, LIBRARY_ELEMENT5);
     expect(task, new isInstanceOf<ResolveLibraryTypeNamesTask>());
     // validate
@@ -2367,13 +2359,6 @@ class C {}
       expect(clazz.displayName, 'A');
       clazz = clazz.supertype.element;
       expect(clazz.displayName, 'B');
-      clazz = clazz.supertype.element;
-      expect(clazz.displayName, 'B2');
-      clazz = clazz.supertype.element;
-      expect(clazz.displayName, 'C');
-      clazz = clazz.supertype.element;
-      expect(clazz.displayName, 'Object');
-      expect(clazz.supertype, isNull);
     }
   }
 }