Fix tests and analysis warnings and release 0.12.0-beta.9.

test/runner/browser/content_shell_test.dart

Index: test/runner/browser/content_shell_test.dart
diff --git a/test/runner/browser/content_shell_test.dart b/test/runner/browser/content_shell_test.dart
index 6d19209864d2f6b6532dec8b58a2c0a6f7938899..f176ca8f421d61dfdc3246de9270cf9e4b448085 100644
--- a/test/runner/browser/content_shell_test.dart
+++ b/test/runner/browser/content_shell_test.dart
@@ -15,6 +15,8 @@ import 'package:test/src/util/io.dart';
 import 'package:test/src/utils.dart';
 import 'package:test/test.dart';
 
+import '../../utils.dart';
+
 void main() {
   group("running Dart", () {
     // The Dart to serve in the server.
@@ -141,6 +143,7 @@ webSocket.onOpen.first.then((_) =>
   test("reports an error in onExit", () {
     var contentShell = new ContentShell("http://dart-lang.org",
         executable: "_does_not_exist");
-    expect(contentShell.onExit, throwsA(new isInstanceOf<ProcessException>()));
+    expect(contentShell.onExit, throwsA(isApplicationException(startsWith(
+        "Failed to start content shell: No such file or directory"))));
   });
 }