Converted Observatory heap-map element

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

Index: runtime/observatory/lib/src/app/page.dart
diff --git a/runtime/observatory/lib/src/app/page.dart b/runtime/observatory/lib/src/app/page.dart
index 945137e3ede53109ae651192356fe894747d7a0e..adc503716adc172a14e8951ff37c3e4d014f16ef 100644
--- a/runtime/observatory/lib/src/app/page.dart
+++ b/runtime/observatory/lib/src/app/page.dart
@@ -399,19 +399,26 @@ class PersistentHandlesPage extends SimplePage {
   }
 }
 
-class HeapMapPage extends SimplePage {
-  HeapMapPage(app) : super('heap-map', 'heap-map', app);
+class HeapMapPage extends MatchingPage {
+  HeapMapPage(app) : super('heap-map', app);
+
+  final DivElement container = new DivElement();
 
   void _visit(Uri uri) {
     super._visit(uri);
     getIsolate(uri).then((isolate) {
-      if (element != null) {
-        /// Update the page.
-        HeapMapElement page = element;
-        page.isolate = isolate;
-      }
+      container.children = [
+        new HeapMapElement(isolate.vm, isolate, app.events, app.notifications,
+                           queue: app.queue)
+      ];
     });
   }
+
+  void onInstall() {
+    if (element == null) {
+      element = container;
+    }
+  }
 }
 
 class HeapSnapshotPage extends MatchingPage {