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 ddc94c77b4cf57a913dd3bdbdf36886fff774d1c..178072497f46b1371c37cae8cf489037fe610d0f 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;
@@ -564,6 +563,8 @@ 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,
@@ -600,8 +601,9 @@ 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 {
@@ -1119,7 +1121,8 @@ 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();