Big merge from experimental to bleeding edge.

tests/corelib/iterable_first_matching_test.dart

+// Copyright (c) 2012, 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.
+
+main() {
+  List<int> list1 = <int>[1, 2, 3];
+  List<int> list2 = const <int>[4, 5];
+  List<String> list3 = <String>[];
+  Set<int> set1 = new Set<int>();
+  set1..add(11)
+      ..add(12)
+      ..add(13);
+  Set set2 = new Set();
+
+  Expect.equals(2, list1.firstMatching((x) => x.isEven));
+  Expect.equals(1, list1.firstMatching((x) => x.isOdd));
+  Expect.throws(() => list1.firstMatching((x) => x > 3),
+                (e) => e is StateError);
+  Expect.equals(null, list1.firstMatching((x) => x > 3, orElse: () => null));
+  Expect.equals(499, list1.firstMatching((x) => x > 3, orElse: () => 499));
+
+  Expect.equals(4, list2.firstMatching((x) => x.isEven));
+  Expect.equals(5, list2.firstMatching((x) => x.isOdd));
+  Expect.throws(() => list2.firstMatching((x) => x == 0),
+                (e) => e is StateError);
+  Expect.equals(null, list2.firstMatching((x) => false, orElse: () => null));
+  Expect.equals(499, list2.firstMatching((x) => false, orElse: () => 499));
+
+  Expect.throws(() => list3.firstMatching((x) => x == 0),
+                (e) => e is StateError);
+  Expect.throws(() => list3.firstMatching((x) => true), (e) => e is StateError);
+  Expect.equals(null, list3.firstMatching((x) => true, orElse: () => null));
+  Expect.equals("str", list3.firstMatching((x) => false, orElse: () => "str"));
+
+  Expect.equals(12, set1.firstMatching((x) => x.isEven));
+  var odd = set1.firstMatching((x) => x.isOdd);
+  Expect.isTrue(odd == 11 || odd == 13);
+  Expect.throws(() => set1.firstMatching((x) => false), (e) => e is StateError);
+  Expect.equals(null, set1.firstMatching((x) => false, orElse: () => null));
+  Expect.equals(499, set1.firstMatching((x) => false, orElse: () => 499));
+
+  Expect.throws(() => set2.firstMatching((x) => false), (e) => e is StateError);
+  Expect.throws(() => set2.firstMatching((x) => true), (e) => e is StateError);
+  Expect.equals(null, set2.firstMatching((x) => true, orElse: () => null));
+  Expect.equals(499, set2.firstMatching((x) => false, orElse: () => 499));
+}