Merge IO v2 branch to bleeding edge

tests/standalone/io/process_exit_test.dart

Index: tests/standalone/io/process_exit_test.dart
diff --git a/tests/standalone/io/process_exit_test.dart b/tests/standalone/io/process_exit_test.dart
index f4f910007d2174853e0217bc63fa11ecab5d3662..060bb14055bb00efebd23490f9d58fa04659d725 100644
--- a/tests/standalone/io/process_exit_test.dart
+++ b/tests/standalone/io/process_exit_test.dart
@@ -12,11 +12,11 @@ testExit() {
   var future = Process.start(getProcessTestFileName(),
                              const ["0", "0", "99", "0"]);
   future.then((process) {
-    process.onExit = (int exitCode) {
+    process.exitCode.then((int exitCode) {
       Expect.equals(exitCode, 99);
-    };
-    process.stdout.onData = process.stdout.read;
-    process.stderr.onData = process.stderr.read;
+    });
+    process.stdout.listen((_) {});
+    process.stderr.listen((_) {});
   });
 }