Reapply "[vm] Don't enable the profiler by default. Enable the profiler at startup with --observe, …

runtime/observatory/lib/src/elements/sample_buffer_control.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:async';
 import 'dart:html';
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/uris.dart';
@@ skipping 11 matching lines @@
   RenderingScheduler<SampleBufferControlElement> _r;
 
   Stream<RenderedEvent<SampleBufferControlElement>> get onRendered =>
       _r.onRendered;
 
   StreamController<SampleBufferControlChangedElement> _onTagChange =
       new StreamController<SampleBufferControlChangedElement>.broadcast();
   Stream<SampleBufferControlChangedElement> get onTagChange =>
       _onTagChange.stream;
 
+  M.VM _vm;
   Stream<M.SampleProfileLoadingProgressEvent> _progressStream;
   M.SampleProfileLoadingProgress _progress;
   M.SampleProfileTag _tag;
   bool _showTag = false;
   bool _profileVM = false;
   StreamSubscription _subscription;
 
   M.SampleProfileLoadingProgress get progress => _progress;
   M.SampleProfileTag get selectedTag => _tag;
   bool get showTag => _showTag;
   bool get profileVM => _profileVM;
 
   set selectedTag(M.SampleProfileTag value) =>
       _tag = _r.checkAndReact(_tag, value);
   set showTag(bool value) => _showTag = _r.checkAndReact(_showTag, value);
   set profileVM(bool value) => _profileVM = _r.checkAndReact(_profileVM, value);
 
-  factory SampleBufferControlElement(M.SampleProfileLoadingProgress progress,
+  factory SampleBufferControlElement(
+      M.VM vm,
+      M.SampleProfileLoadingProgress progress,
       Stream<M.SampleProfileLoadingProgressEvent> progressStream,
       {M.SampleProfileTag selectedTag: M.SampleProfileTag.none,
       bool showTag: true,
       RenderingQueue queue}) {
+    assert(vm != null);
     assert(progress != null);
     assert(progressStream != null);
     assert(selectedTag != null);
     assert(showTag != null);
     SampleBufferControlElement e = document.createElement(tag.name);
     e._r = new RenderingScheduler(e, queue: queue);
+    e._vm = vm;
     e._progress = progress;
     e._progressStream = progressStream;
     e._tag = selectedTag;
     e._showTag = showTag;
     return e;
   }
 
   SampleBufferControlElement.created() : super.created();
 
   @override
@@ skipping 52 matching lines @@
             ..text = message,
           new DivElement()
             ..style.background = '#0489c3'
             ..style.width = '$progress%'
             ..style.height = '15px'
             ..style.borderRadius = '4px'
         ]
     ];
   }
 
-  static List<Element> _createDisabledMessage() {
+  List<Element> _createDisabledMessage() {
     return [
       new DivElement()
         ..classes = ['statusBox' 'shadow' 'center']
         ..children = [
           new DivElement()
             ..children = [
               new HeadingElement.h1()..text = 'Profiling is disabled',
               new BRElement(),
               new DivElement()
                 ..innerHtml = 'Perhaps the <b>profile</b> '
                     'flag has been disabled for this VM.',
               new BRElement(),
-              new SpanElement()..text = 'See all ',
-              new AnchorElement(href: Uris.flags())..text = 'vm flags'
+              new ButtonElement()
+                ..text = 'Enable profiler'
+                ..onClick.listen((_) {
+                  _enableProfiler();
+                })
             ]
         ]
     ];
   }
 
   List<Element> _createStatusReport() {
     final fetchT = Utils.formatDurationInSeconds(_progress.fetchingTime);
     final loadT = Utils.formatDurationInSeconds(_progress.loadingTime);
     final sampleCount = _progress.profile.sampleCount;
     final refreshT = new DateTime.now();
@@ skipping 89 matching lines @@
       case M.SampleProfileTag.none:
         return 'None';
     }
     throw new Exception('Unknown tagToString');
   }
 
   SampleBufferControlChangedElement _toEvent(_) {
     return new SampleBufferControlChangedElement(this);
   }
 
+  void _enableProfiler() {
+    _vm.enableProfiler().then((_) {
+      _triggerModeChange(_toEvent(null));
+    });
+  }
+
   void _triggerModeChange(e) => _onTagChange.add(e);
 }