Add a version of heap snapshots that use only fields and stack frames as roots and only include ins…

runtime/observatory/lib/src/repositories/heap_snapshot.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 HeapSnapshotLoadingProgressEvent
     implements M.HeapSnapshotLoadingProgressEvent {
   final HeapSnapshotLoadingProgress progress;
   HeapSnapshotLoadingProgressEvent(this.progress);
 }
 
 class HeapSnapshotLoadingProgress extends M.HeapSnapshotLoadingProgress {
   StreamController<HeapSnapshotLoadingProgressEvent> _onProgress =
       new StreamController<HeapSnapshotLoadingProgressEvent>.broadcast();
   Stream<HeapSnapshotLoadingProgressEvent> get onProgress => _onProgress.stream;
 
   final S.Isolate isolate;
+  final M.HeapSnapshotRoots roots;
   final bool gc;
 
   M.HeapSnapshotLoadingStatus _status = M.HeapSnapshotLoadingStatus.fetching;
   String _stepDescription = '';
   double _progress = 0.0;
   final Stopwatch _fetchingTime = new Stopwatch();
   final Stopwatch _loadingTime = new Stopwatch();
   HeapSnapshot _snapshot;
 
   M.HeapSnapshotLoadingStatus get status => _status;
   String get stepDescription => _stepDescription;
   double get progress => _progress;
   Duration get fetchingTime => _fetchingTime.elapsed;
   Duration get loadingTime => _loadingTime.elapsed;
   HeapSnapshot get snapshot => _snapshot;
 
-  HeapSnapshotLoadingProgress(this.isolate, this.gc) {
+  HeapSnapshotLoadingProgress(this.isolate, this.roots, this.gc) {
     _run();
   }
 
   Future _run() async {
     _fetchingTime.start();
     try {
       _status = M.HeapSnapshotLoadingStatus.fetching;
       _triggerOnProgress();
 
       await isolate.getClassRefs();
 
-      final stream = isolate.fetchHeapSnapshot(gc);
+      final stream = isolate.fetchHeapSnapshot(roots, gc);
 
       stream.listen((status) {
         if (status is List) {
           _progress = status[0] * 100.0 / status[1];
           _stepDescription = 'Receiving snapshot chunk ${status[0] + 1}'
               ' of ${status[1]}...';
           _triggerOnProgress();
         }
       });
 
@@ skipping 34 matching lines @@
     _onProgress =
         new StreamController<HeapSnapshotLoadingProgressEvent>.broadcast();
     (() async {
       _triggerOnProgress();
       _onProgress.close();
     }());
   }
 }
 
 class HeapSnapshotRepository implements M.HeapSnapshotRepository {
-  Stream<HeapSnapshotLoadingProgressEvent> get(M.IsolateRef i,
-      {bool gc: false}) {
+  Stream<HeapSnapshotLoadingProgressEvent> get(
+      M.IsolateRef i,
+      {M.HeapSnapshotRoots roots: M.HeapSnapshotRoots.vm,
+      bool gc: false}) {
     S.Isolate isolate = i as S.Isolate;
     assert(isolate != null);
     assert(gc != null);
-    return new HeapSnapshotLoadingProgress(isolate, gc).onProgress;
+    return new HeapSnapshotLoadingProgress(isolate, roots, gc).onProgress;
   }
 }