Make VM event streams look like real dart streams.

runtime/observatory/tests/service/test_helper.dart

Index: runtime/observatory/tests/service/test_helper.dart
diff --git a/runtime/observatory/tests/service/test_helper.dart b/runtime/observatory/tests/service/test_helper.dart
index e69a257e427602dea8d89f5587c0d2bd17641276..b9f3c7be42994627c1bdb48d052d30e969962372 100644
--- a/runtime/observatory/tests/service/test_helper.dart
+++ b/runtime/observatory/tests/service/test_helper.dart
@@ -141,11 +141,15 @@ typedef void ServiceEventHandler(ServiceEvent event,
                                  StreamSubscription subscription,
                                  Completer completer);
 
-Future processServiceEvents(VM vm, ServiceEventHandler handler) {
+Future processServiceEvents(VM vm,
+                            String streamId,
+                            ServiceEventHandler handler) {
   Completer completer = new Completer();
-  var subscription;
-  subscription = vm.events.stream.listen((ServiceEvent event) {
-    handler(event, subscription, completer);
+  vm.getEventStream(streamId).then((stream) {
+    var subscription;
+    subscription = stream.listen((ServiceEvent event) {
+      handler(event, subscription, completer);
+    });
   });
   return completer.future;
 }
@@ -161,13 +165,15 @@ Future<Isolate> hasStoppedAtBreakpoint(Isolate isolate) {
 
   // Set up a listener to wait for breakpoint events.
   Completer completer = new Completer();
-  var subscription;
-  subscription = isolate.vm.events.stream.listen((ServiceEvent event) {
-    if (event.kind == ServiceEvent.kPauseBreakpoint) {
-      print('Breakpoint reached');
-      subscription.cancel();
-      completer.complete(isolate);
-    }
+  isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
+    var subscription;
+    subscription = stream.listen((ServiceEvent event) {
+        if (event.kind == ServiceEvent.kPauseBreakpoint) {
+          print('Breakpoint reached');
+          subscription.cancel();
+          completer.complete();
+        }
+    });
   });
 
   return completer.future;  // Will complete when breakpoint hit.
@@ -176,12 +182,14 @@ Future<Isolate> hasStoppedAtBreakpoint(Isolate isolate) {
 
 Future<Isolate> resumeIsolate(Isolate isolate) {
   Completer completer = new Completer();
-  var subscription;
-  subscription = isolate.vm.events.stream.listen((ServiceEvent event) {
-    if (event.kind == ServiceEvent.kResume) {
-      subscription.cancel();
-      completer.complete();
-    }
+  isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
+    var subscription;
+    subscription = stream.listen((ServiceEvent event) {
+      if (event.kind == ServiceEvent.kResume) {
+        subscription.cancel();
+        completer.complete();
+      }
+    });
   });
   isolate.resume();
   return completer.future;