Remove the dependency of Zone on Isolate

test/cctest/test-ast.cc

 // Copyright 2012 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 20 matching lines @@
 
 #include "src/ast.h"
 #include "test/cctest/cctest.h"
 
 using namespace v8::internal;
 
 TEST(List) {
   List<AstNode*>* list = new List<AstNode*>(0);
   CHECK_EQ(0, list->length());
 
-  Isolate* isolate = CcTest::i_isolate();
-  Zone zone(isolate);
+  Zone zone;
   AstValueFactory value_factory(&zone, 0);
   AstNodeFactory factory(&value_factory);
   AstNode* node = factory.NewEmptyStatement(RelocInfo::kNoPosition);
   list->Add(node);
   CHECK_EQ(1, list->length());
   CHECK_EQ(node, list->at(0));
   CHECK_EQ(node, list->last());
 
   const int kElements = 100;
   for (int i = 0; i < kElements; i++) {
     list->Add(node);
   }
   CHECK_EQ(1 + kElements, list->length());
 
   list->Clear();
   CHECK_EQ(0, list->length());
   delete list;
 }