[turbofan] add absolute peak to stats

src/compiler/pipeline-statistics.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_PIPELINE_STATISTICS_H_
 #define V8_COMPILER_PIPELINE_STATISTICS_H_
 
 #include <string>
 
 #include "src/compilation-statistics.h"
@@ skipping 21 matching lines @@
    public:
     CommonStats() : outer_zone_initial_size_(0) {}
 
     void Begin(PipelineStatistics* pipeline_stats);
     void End(PipelineStatistics* pipeline_stats,
              CompilationStatistics::BasicStats* diff);
 
     SmartPointer<ZonePool::StatsScope> scope_;
     base::ElapsedTimer timer_;
     size_t outer_zone_initial_size_;
+    size_t allocated_bytes_at_start_;
   };
 
   bool InPhaseKind() { return !phase_kind_stats_.scope_.is_empty(); }
   void EndPhaseKind();
 
   friend class PhaseScope;
   bool InPhase() { return !phase_stats_.scope_.is_empty(); }
   void BeginPhase(const char* name);
   void EndPhase();
 
@@ skipping 33 matching lines @@
   PipelineStatistics* const pipeline_stats_;
 
   DISALLOW_COPY_AND_ASSIGN(PhaseScope);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif