Fix running browser tests in subdirectories and release 0.12.0-beta.10.

test/runner/browser/runner_test.dart

Index: test/runner/browser/runner_test.dart
diff --git a/test/runner/browser/runner_test.dart b/test/runner/browser/runner_test.dart
index 60ec848c71b4fc567e5cee3adf566e7788a48a65..5bad1c55db9965e99c69ec01e7dd49fc888937b3 100644
--- a/test/runner/browser/runner_test.dart
+++ b/test/runner/browser/runner_test.dart
@@ -298,6 +298,15 @@ void main() {
       expect(result.exitCode, equals(0));
     });
 
+    // Regression test; this broke in 0.12.0-beta.9.
+    test("on a file in a subdirectory", () {
+      new Directory(p.join(_sandbox, "dir")).createSync();
+      new File(p.join(_sandbox, "dir", "test.dart"))
+          .writeAsStringSync(_success);
+      var result = _runUnittest(["-p", "chrome", "dir/test.dart"]);
+      expect(result.exitCode, equals(0));
+    });
+
     group("with a custom HTML file", () {
       setUp(() {
         new File(p.join(_sandbox, "test.dart")).writeAsStringSync("""