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