Cleanup some Observatory errors caught by dart2js

runtime/observatory/lib/src/elements/debugger.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.
 
 library debugger_page_element;
 
 import 'dart:async';
 import 'dart:svg';
 import 'dart:html';
 import 'dart:math';
@@ skipping 2030 matching lines @@
       // a range, don't interfere.
       var selection = window.getSelection();
       if (selection == null ||
           (selection.type != 'Range' && selection.type != 'text')) {
         _debugger.input.focus();
       }
     });
   }
 
   @override
+  void render() {
+    /* nothing to do */
+  }
+
+  @override
   void detached() {
     _timer.cancel();
     children = const [];
     S.cancelFutureSubscription(_vmSubscriptionFuture);
     _vmSubscriptionFuture = null;
     S.cancelFutureSubscription(_isolateSubscriptionFuture);
     _isolateSubscriptionFuture = null;
     S.cancelFutureSubscription(_debugSubscriptionFuture);
     _debugSubscriptionFuture = null;
     S.cancelFutureSubscription(_stdoutSubscriptionFuture);
@@ skipping 100 matching lines @@
         ..text = 'No stack',
       e._frameList = new UListElement()..classes = ['list-group'],
       new HRElement(),
       e._hasMessages = new DivElement()..classes = ['noMessages', 'hidden']
         ..text = 'No pending messages',
       e._messageList = new UListElement()..classes = ['messageList']
     ];
     return e;
   }
 
+  void render() {
+    /* nothing to do */
+  }
+
   _addFrame(List frameList, S.Frame frameInfo) {
     final frameElement = new DebuggerFrameElement(_isolate,
                                                   frameInfo,
                                                   _scroller,
                                                   _instances,
                                                   _scripts,
                                                   _events,
                                                   queue: app.queue);
 
     if (frameInfo.index == currentFrame) {
@@ skipping 738 matching lines @@
   }
 
   void newline() {
     _append(new BRElement());
   }
 
   void clear() {
     children.clear();
   }
 
+  void render() {
+    /* nothing to do */
+  }
+
   ObservatoryApplication get app => ObservatoryApplication.app;
 }
 
 class DebuggerInputElement extends HtmlElement implements Renderable {
   static const tag = const Tag<DebuggerInputElement>('debugger-input');
 
   S.Isolate _isolate;
   ObservatoryDebugger _debugger;
   bool _busy = false;
   final _modalPromptDiv = new DivElement()
@@ skipping 154 matching lines @@
 
   void exitMode() {
     assert(modalPrompt != null);
     modalPrompt = null;
     modalCallback = null;
   }
 
   void focus() {
     _textBox.focus();
   }
+
+  void render() {
+    // Nothing to do.
+  }
 }
 
 final SvgSvgElement iconExpandLess = new SvgSvgElement()
     ..setAttribute('width', '24')
     ..setAttribute('height', '24')
     ..children = [
       new PolygonElement()
         ..setAttribute('points', '12,8 6,14 7.4,15.4 12,10.8 16.6,15.4 18,14 ')
     ];
 
@@ skipping 55 matching lines @@
 final SvgSvgElement iconInfoOutline = new SvgSvgElement()
     ..setAttribute('width', '24')
     ..setAttribute('height', '24')
     ..children = [
       new PathElement()
         ..setAttribute('d', 'M11 17h2v-6h-2v6zm1-15C6.48 2 2 6.48 2 12s4.48 10 '
                             '10 10 10-4.48 10-10S17.52 2 12 2zm0 18c-4.41 '
                             '0-8-3.59-8-8s3.59-8 8-8 8 3.59 8 8-3.59 8-8 8zM11 '
                             '9h2V7h-2v2z')
     ];