External references should not affect dominance relation.

src/profile-generator.h

Index: src/profile-generator.h
diff --git a/src/profile-generator.h b/src/profile-generator.h
index b9de69bce33d7f4866b609b9081c6c0df1b427b7..75694c23f7246a55b95b768a2248076d58464b9e 100644
--- a/src/profile-generator.h
+++ b/src/profile-generator.h
@@ -477,8 +477,7 @@ class HeapGraphEdge BASE_EMBEDDED {
     return name_;
   }
   HeapEntry* to() { return to_; }
-
-  HeapEntry* From();
+  INLINE(HeapEntry* from());
 
  private:
   int child_index_ : 29;
@@ -562,6 +561,8 @@ class HeapEntry BASE_EMBEDDED {
   void clear_paint() { painted_ = false; }
   bool painted() { return painted_; }
   void paint() { painted_ = true; }
+  bool reachable_from_window() { return reachable_from_window_; }
+  void set_reachable_from_window() { reachable_from_window_ = true; }
 
   void SetIndexedReference(HeapGraphEdge::Type type,
                            int child_index,
@@ -598,8 +599,9 @@ class HeapEntry BASE_EMBEDDED {
   const char* TypeAsString();
 
   unsigned painted_: 1;
+  unsigned reachable_from_window_: 1;

[mnaganov (inactive), 2012/04/05 22:00:13]

Do we really need an additional field? It seems that 'painted_' bit is only used
in FillPostorderIndexes. We can first fill the indexes, and then mark reachable
objects, reusing the same bit. 

[alexeif, 2012/04/06 10:04:36]

They both are in use in FillPostorderIndexes.

[mnaganov (inactive), 2012/04/06 14:16:01]

Sorry, didn't realize that. It is queried in IsRetainingEdge.

   unsigned type_: 4;
-  int children_count_: 27;
+  int children_count_: 26;
   int retainers_count_;
   int self_size_;
   union {
@@ -1097,7 +1099,8 @@ class HeapSnapshotGenerator : public SnapshottingProgressReportingInterface {
   bool CalculateRetainedSizes();
   bool CountEntriesAndReferences();
   bool FillReferences();
-  void FillReversePostorderIndexes(Vector<HeapEntry*>* entries);
+  void FillPostorderIndexes(Vector<HeapEntry*>* entries);

[mnaganov (inactive), 2012/04/05 22:00:13]

Why the rename? "Reverse" means that children will have order indexes in reverse
to their child index, as we are processing them backwards.

[alexeif, 2012/04/06 10:04:36]

This algorithm assigns postorder indexes which means the parent is processed
after its nodes. AFAICT word "Reverse" came from the dominators building
algorithm where we're processing postorder sorted nodes in reverse order. So the
word reverse has no relation to this particular function, thus I removed it.

[alexeif, 2012/04/06 10:07:11]

typo: read "after its children".

+  void MarkWindowReachableObjects();
   void ProgressStep();
   bool ProgressReport(bool force = false);
   bool SetEntriesDominators();