Speedup dominators construction in heap snapshot.

src/profile-generator.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1083 matching lines @@
 
 class HeapSnapshotGenerator : public SnapshottingProgressReportingInterface {
  public:
   HeapSnapshotGenerator(HeapSnapshot* snapshot,
                         v8::ActivityControl* control);
   bool GenerateSnapshot();
 
  private:
   bool ApproximateRetainedSizes();
   bool BuildDominatorTree(const Vector<HeapEntry*>& entries,
-                          Vector<HeapEntry*>* dominators);
+                          Vector<int>* dominators);
   bool CountEntriesAndReferences();
   bool FillReferences();
   void FillReversePostorderIndexes(Vector<HeapEntry*>* entries);
   void ProgressStep();
   bool ProgressReport(bool force = false);
   bool SetEntriesDominators();
   void SetProgressTotal(int iterations_count);
 
   HeapSnapshot* snapshot_;
   v8::ActivityControl* control_;
@@ skipping 57 matching lines @@
 
   friend class HeapSnapshotJSONSerializerEnumerator;
   friend class HeapSnapshotJSONSerializerIterator;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotJSONSerializer);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROFILE_GENERATOR_H_