Remove the dependency of Zone on Isolate

src/compiler/raw-machine-assembler.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_RAW_MACHINE_ASSEMBLER_H_
 #define V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 
 #include "src/v8.h"
 
 #include "src/compiler/common-operator.h"
@@ skipping 26 matching lines @@
     explicit Label(BasicBlock* block)
         : block_(block), used_(false), bound_(false) {}
 
     BasicBlock* block_;
     bool used_;
     bool bound_;
     friend class RawMachineAssembler;
     DISALLOW_COPY_AND_ASSIGN(Label);
   };
 
-  RawMachineAssembler(Graph* graph, MachineSignature* machine_sig,
+  RawMachineAssembler(Isolate* isolate, Graph* graph,
+                      MachineSignature* machine_sig,
                       MachineType word = kMachPtr,
                       MachineOperatorBuilder::Flags flags =
                           MachineOperatorBuilder::Flag::kNoFlags);
   ~RawMachineAssembler() OVERRIDE {}
 
-  Isolate* isolate() const { return zone()->isolate(); }
   Zone* zone() const { return graph()->zone(); }
   MachineOperatorBuilder* machine() { return &machine_; }
   CommonOperatorBuilder* common() { return &common_; }
   CallDescriptor* call_descriptor() const { return call_descriptor_; }
   size_t parameter_count() const { return machine_sig_->parameter_count(); }
   MachineSignature* machine_sig() const { return machine_sig_; }
 
   Node* UndefinedConstant() {
     Unique<HeapObject> unique = Unique<HeapObject>::CreateImmovable(
         isolate()->factory()->undefined_value());
@@ skipping 391 matching lines @@
   BasicBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(RawMachineAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_