Observatory: Fix allocation profile CVS export. Fix heap snapshot in/out reference counts.

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

Index: runtime/observatory/lib/src/elements/heap_snapshot.dart
diff --git a/runtime/observatory/lib/src/elements/heap_snapshot.dart b/runtime/observatory/lib/src/elements/heap_snapshot.dart
index 51c451e414e50751edc06b29dee362acab2e7b06..a3ce8d236baf38dd6be1acd44fda19d092886c91 100644
--- a/runtime/observatory/lib/src/elements/heap_snapshot.dart
+++ b/runtime/observatory/lib/src/elements/heap_snapshot.dart
@@ -346,12 +346,16 @@ class HeapSnapshotElement  extends HtmlElement implements Renderable {
         element.children[2].text = '';
       }
       element.children[3].text = '';
+      int references = 0;
+      for (var referenceGroup in item) {
+        references += referenceGroup.count;
+      }
       if (item is Iterable<M.HeapSnapshotClassInbound>) {
         element.children[4] = new SpanElement()..classes = ['name']
-            ..text = '${item.length} Incoming references';
+            ..text = '$references incoming references';
       } else {
         element.children[4] = new SpanElement()..classes = ['name']
-            ..text = '${item.length} Outgoing references';
+            ..text = '$references outgoing references';
       }
     } else {
       element.children[0].text = '';