Remove the dependency of Zone on Isolate

src/compiler/code-generator.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_CODE_GENERATOR_H_
 #define V8_COMPILER_CODE_GENERATOR_H_
 
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/instruction.h"
 #include "src/deoptimizer.h"
@@ skipping 20 matching lines @@
 class CodeGenerator FINAL : public GapResolver::Assembler {
  public:
   explicit CodeGenerator(Frame* frame, Linkage* linkage,
                          InstructionSequence* code, CompilationInfo* info);
 
   // Generate native code.
   Handle<Code> GenerateCode();
 
   InstructionSequence* code() const { return code_; }
   Frame* frame() const { return frame_; }
-  Isolate* isolate() const { return zone()->isolate(); }
+  Isolate* isolate() const { return info_->isolate(); }
   Linkage* linkage() const { return linkage_; }
 
   Label* GetLabel(BasicBlock::RpoNumber rpo) { return &labels_[rpo.ToSize()]; }
 
  private:
   MacroAssembler* masm() { return &masm_; }
   GapResolver* resolver() { return &resolver_; }
   SafepointTableBuilder* safepoints() { return &safepoints_; }
   Zone* zone() const { return code()->zone(); }
   CompilationInfo* info() const { return info_; }
@@ skipping 95 matching lines @@
   int last_lazy_deopt_pc_;
   OutOfLineCode* ools_;
   int osr_pc_offset_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CODE_GENERATOR_H