Reapply "Remove @deprecated features."

runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart

Index: runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart
diff --git a/runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart b/runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart
index 8dfa43e4ba7528b8baca973d5815d4dbd8a08d6a..cc85580e1d16096db16a6b20e8158cc047407de8 100644
--- a/runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart
+++ b/runtime/bin/vmservice/client/lib/src/observatory_elements/message_viewer.dart
@@ -14,8 +14,8 @@ class MessageViewerElement extends ObservatoryElement {
 
   @published set message(Map m) {
     _message = m;
-    notifyProperty(this, #messageType);
-    notifyProperty(this, #members);
+    this.notifyPropertyChange(#messageType, null, null);
+    this.notifyPropertyChange(#members, null, null);
   }
 
   String get messageType {
@@ -31,4 +31,4 @@ class MessageViewerElement extends ObservatoryElement {
     }
     return message['members'];
   }
-}
+}