Add memory-dashboard page to Observatory

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 87 matching lines @@
     var isolateId = uri.queryParameters['isolateId'];
     return app.vm.getIsolate(isolateId).then((isolate) {
       if (isolate == null) {
         throw new IsolateNotFound(isolateId);
       }
       return isolate;
     });
   }
 
   EditorRepository getEditor(Uri uri) {
-    var editor = uri.queryParameters['editor'];
-    if (editor != null) {
-      return new EditorRepository(editor);
-    }
+    final editor = uri.queryParameters['editor'];
+    return new EditorRepository(app.vm, editor: editor);
     return null;
   }
 
   bool canVisit(Uri uri) => uri.path == path;
 }
 
 /// A [SimplePage] matches a single uri path and displays a single element.
 class SimplePage extends MatchingPage {
   final String elementTagName;
   SimplePage(String path, this.elementTagName, app) : super(path, app);
@@ skipping 570 matching lines @@
   }
 }
 
 class MemoryDashboardPage extends MatchingPage {
   MemoryDashboardPage(app) : super('memory-dashboard', app);
 
   final DivElement container = new DivElement();
 
   void _visit(Uri uri) {
     super._visit(uri);
-    getIsolate(uri).then((isolate) {
+    if (app.vm == null) {
+      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(isolate.vm, isolate, app.events,
-            app.notifications, _allocationProfileRepository, getEditor(uri),
+        new MemoryDashboardElement(vm, new IsolateRepository(vm), editor,
+            _allocationProfileRepository, 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() {
     if (element == null) {
       element = container;
     }
     app.startGCEventListener();
   }
 
@@ skipping 235 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';
 }