Re-apply "Remove unittest and matcher from the repo."

pkg/unittest/lib/src/group_context.dart

Index: pkg/unittest/lib/src/group_context.dart
diff --git a/pkg/unittest/lib/src/group_context.dart b/pkg/unittest/lib/src/group_context.dart
deleted file mode 100644
index d44b6cd3fec4a21a7c82ab2795b99fa5cd06e5ce..0000000000000000000000000000000000000000
--- a/pkg/unittest/lib/src/group_context.dart
+++ /dev/null
@@ -1,65 +0,0 @@
-part of unittest;
-
-/// Setup and teardown functions for a group and its parents, the latter
-/// for chaining.
-class _GroupContext {
-  final _GroupContext parent;
-
-  /// Description text of the current test group.
-  final String _name;
-
-  /// Setup function called before each test in a group.
-  Function _testSetup;
-
-  get testSetup => _testSetup;
-
-  get parentSetup => (parent == null) ? null : parent.testSetup;
-
-  set testSetup(Function setup) {
-    var preSetup = parentSetup;
-    if (preSetup == null) {
-      _testSetup = setup;
-    } else {
-      _testSetup = () {
-        var f = preSetup();
-        if (f is Future) {
-          return f.then((_) => setup());
-        } else {
-          return setup();
-        }
-      };
-    }
-  }
-
-  /// Teardown function called after each test in a group.
-  Function _testTeardown;
-
-  get testTeardown => _testTeardown;
-
-  get parentTeardown => (parent == null) ? null : parent.testTeardown;
-
-  set testTeardown(Function teardown) {
-    var postTeardown = parentTeardown;
-    if (postTeardown == null) {
-      _testTeardown = teardown;
-    } else {
-      _testTeardown = () {
-        var f = teardown();
-        if (f is Future) {
-          return f.then((_) => postTeardown());
-        } else {
-          return postTeardown();
-        }
-      };
-    }
-  }
-
-  String get fullName => (parent == null || parent == _environment.rootContext)
-      ? _name
-      : "${parent.fullName}$groupSep$_name";
-
-  _GroupContext([this.parent, this._name = '']) {
-    _testSetup = parentSetup;
-    _testTeardown = parentTeardown;
-  }
-}