Add memory-dashboard page to Observatory

runtime/observatory/lib/src/repositories/editor.dart

 // Copyright (c) 2016, 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 repositories;
 
 class EditorRepository extends M.EditorRepository {
-  final String editor;
+  final S.VM _vm;
+  final String _editor;
 
-  EditorRepository(this.editor) {
-    assert(this.editor != null);
+  bool get canOpenClass => _getService() != null;
+
+  EditorRepository(S.VM vm, {String editor})
+      : _vm = vm,
+        _editor = editor {
+    assert(_vm != null);
   }
 
-  Future<M.Sentinel> sendObject(M.IsolateRef i, M.ObjectRef object) {
+  S.Service _getService() {
+    if (_vm.services.isEmpty) {
+      return null;
+    }
+    if (_editor == null) {
+      return _vm.services.where((s) => s.service == 'openSourceLocation').first;
+    }
+    return _vm.services
+        .where((s) => s.service == 'openSourceLocation' && s.alias == _editor)
+        .single;
+  }
+
+  Future openClass(M.IsolateRef i, M.ClassRef c) async {
+    S.Class clazz = c as S.Class;
+    assert(clazz != null);
+    if (!clazz.loaded) {
+      await clazz.load();
+    }
+    if (clazz.location == null) {
+      return new Future.value();
+    }
+    return await openSourceLocation(i, clazz.location);
+  }
+
+  Future openSourceLocation(M.IsolateRef i, M.SourceLocation l) async {
     final isolate = i as S.Isolate;
     assert(isolate != null);
-    return isolate.invokeRpc(
-        '_sendObjectToEditor', {'editor': editor, 'objectId': object.id});
+    assert(l != null);
+    return await isolate.invokeRpc(_getService().method,
+        {'scriptId': l.script.id, 'tokenPos': l.tokenPos});
   }
 }