Remove the dependency of Zone on Isolate

src/compiler/pipeline-statistics.cc

 // 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.
 
 #include "src/compiler.h"
 #include "src/compiler/pipeline-statistics.h"
 #include "src/compiler/zone-pool.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 25 matching lines @@
       diff->max_allocated_bytes_ + allocated_bytes_at_start_;
   diff->total_allocated_bytes_ =
       outer_zone_diff + scope_->GetTotalAllocatedBytes();
   scope_.Reset(NULL);
   timer_.Stop();
 }
 
 
 PipelineStatistics::PipelineStatistics(CompilationInfo* info,
                                        ZonePool* zone_pool)
-    : isolate_(info->zone()->isolate()),
+    : isolate_(info->isolate()),
       outer_zone_(info->zone()),
       zone_pool_(zone_pool),
       compilation_stats_(isolate_->GetTurboStatistics()),
       source_size_(0),
       phase_kind_name_(NULL),
       phase_name_(NULL) {
   if (!info->shared_info().is_null()) {
     source_size_ = static_cast<size_t>(info->shared_info()->SourceSize());
     SmartArrayPointer<char> name =
         info->shared_info()->DebugName()->ToCString();
@@ skipping 37 matching lines @@
 void PipelineStatistics::EndPhase() {
   DCHECK(InPhaseKind());
   CompilationStatistics::BasicStats diff;
   phase_stats_.End(this, &diff);
   compilation_stats_->RecordPhaseStats(phase_kind_name_, phase_name_, diff);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8