Introduce heap snapshot into Memory Dashboard

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

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of app;
 
 final _allocationProfileRepository = new AllocationProfileRepository();
 final _breakpointRepository = new BreakpointRepository();
 final _classRepository = new ClassRepository();
 final _classSampleProfileRepository = new ClassSampleProfileRepository();
@@ skipping 691 matching lines @@
       Logger.root.severe('MemoryDashboard has no VM');
       // Reroute to vm-connect.
       app.locationManager.go(Uris.vmConnect());
       return;
     }
     final editor = getEditor(uri);
     app.vm.reload().then((VM vm) async {
       // Preload all isolates to avoid sorting problems.
       await Future.wait(vm.isolates.map((i) => i.load()));
       container.children = [
-        new MemoryDashboardElement(vm, _vmrepository, new IsolateRepository(vm),
-            editor, _allocationProfileRepository, app.events, app.notifications,
+        new MemoryDashboardElement(
+            vm,
+            _vmrepository,
+            new IsolateRepository(vm),
+            editor,
+            _allocationProfileRepository,
+            _heapSnapshotRepository,
+            _objectRepository,
+            app.events,
+            app.notifications,
             queue: app.queue)
       ];
     }).catchError((e, stack) {
       Logger.root.severe('MemoryDashboard visit error: $e');
       // Reroute to vm-connect.
       app.locationManager.go(Uris.vmConnect());
     });
   }
 
   void onInstall() {
@@ skipping 241 matching lines @@
     element = new TimelinePageElement(app.vm, app.events, app.notifications,
         queue: app.queue);
   }
 
   void _visit(Uri uri) {
     assert(canVisit(uri));
   }
 
   bool canVisit(Uri uri) => uri.path == 'timeline';
 }