Better implementation of shutdown timeout.

pkg/analysis_server/test/integration/integration_tests.dart

Index: pkg/analysis_server/test/integration/integration_tests.dart
diff --git a/pkg/analysis_server/test/integration/integration_tests.dart b/pkg/analysis_server/test/integration/integration_tests.dart
index 59c3f321a5f32be02fd6c197d3bb1aebbc83dbca..3447a9f4dbb936e59b87e41f85faec977277be79 100644
--- a/pkg/analysis_server/test/integration/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/integration_tests.dart
@@ -168,15 +168,9 @@ abstract class AbstractAnalysisServerIntegrationTest {
     // doesn't exit, then forcibly terminate it.
     Completer processExited = new Completer();
     server.send(SERVER_SHUTDOWN, null);
-    server.exitCode.whenComplete(() {
-      processExited.complete();
+    return server.exitCode.timeout(SHUTDOWN_TIMEOUT, onTimeout: () {
+      return server.kill();
     });
-    new Future.delayed(SHUTDOWN_TIMEOUT).then((_) {
-      if (!processExited.isCompleted) {
-        server.kill();
-      }
-    });
-    return processExited.future;
   }
 }