Converted Observatory heap-profile element

runtime/observatory/lib/src/app/application.dart

Index: runtime/observatory/lib/src/app/application.dart
diff --git a/runtime/observatory/lib/src/app/application.dart b/runtime/observatory/lib/src/app/application.dart
index d72994d49dd963e55382f5643ccf0f08e217c5a7..3ab1142e73114a9491b5799a5a7c827d4812b878 100644
--- a/runtime/observatory/lib/src/app/application.dart
+++ b/runtime/observatory/lib/src/app/application.dart
@@ -25,6 +25,7 @@ class ObservatoryApplication extends Observable {
       return;
     }
     if (_vm != null) {
+      _gcSubscription = null;
       // Disconnect from current VM.
       notifications.deleteAll();
       _vm.disconnect();
@@ -51,6 +52,25 @@ class ObservatoryApplication extends Observable {
     }
     _vm = vm;
   }
+
+  StreamSubscription _gcSubscription;
+
+  Future startGCEventListener() async {
+    if (_gcSubscription != null || _vm == null) {
+      return;
+    }
+    _gcSubscription = await _vm.listenEventStream(VM.kGCStream, _onEvent);
+  }
+
+  Future stopGCEventListener() async {
+    if (_gcSubscription == null) {
+      return;
+    }
+    _gcSubscription.cancel();
+    _gcSubscription = null;
+  }
+
+
   @reflectable final ObservatoryApplicationElement rootElement;
 
   TraceViewElement _traceView = null;
@@ -138,6 +158,9 @@ class ObservatoryApplication extends Observable {
         e = new InspectEvent(event.timestamp, event.isolate,
             event.inspectee);
         break;
+      case ServiceEvent.kGC:
+        e = new GCEvent(event.timestamp, event.isolate);
+        break;
       default:
         // Ignore unrecognized events.
         Logger.root.severe('Unrecognized event: $event');