Get rid of the ZoneScopeMode.

src/hydrogen-gvn.cc

 // 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 348 matching lines @@
     }
   }
 }
 
 
 HGlobalValueNumberer::HGlobalValueNumberer(HGraph* graph, CompilationInfo* info)
       : graph_(graph),
         info_(info),
         removed_side_effects_(false),
         phase_zone_(info->phase_zone()),
-        phase_zone_scope_(phase_zone_, DELETE_ON_EXIT),
+        phase_zone_scope_(phase_zone_),
         block_side_effects_(graph->blocks()->length(), phase_zone_),
         loop_side_effects_(graph->blocks()->length(), phase_zone_),
         visited_on_paths_(phase_zone_, graph->blocks()->length()) {
     ASSERT(!AllowHandleAllocation::IsAllowed());
     block_side_effects_.AddBlock(GVNFlagSet(), graph_->blocks()->length(),
                                  phase_zone_);
     loop_side_effects_.AddBlock(GVNFlagSet(), graph_->blocks()->length(),
                                 phase_zone_);
   }
 
@@ skipping 469 matching lines @@
                                                       dominated);
         successor_map->Kill(side_effects_on_all_paths);
         successor_dominators->Kill(side_effects_on_all_paths);
       }
     }
     current = next;
   }
 }
 
 } }  // namespace v8::internal