Reduce queue size in dead code elimination by eagerly processing live instructions.

src/hydrogen-dce.h

 // Copyright 2013 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 27 matching lines @@
  public:
   explicit HDeadCodeEliminationPhase(HGraph* graph)
       : HPhase("H_Dead code elimination", graph) { }
 
   void Run() {
     MarkLiveInstructions();
     RemoveDeadInstructions();
   }
 
  private:
-  bool MarkLive(HValue* ref, HValue* instr);
+  void MarkLive(HValue* instr, ZoneList<HValue*>* worklist);
+  void PrintLive(HValue* ref, HValue* instr);
   void MarkLiveInstructions();
   void RemoveDeadInstructions();
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_DCE_H_