Remove the dependency of Zone on Isolate

test/unittests/compiler/zone-pool-unittest.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/base/utils/random-number-generator.h"
 #include "src/compiler/zone-pool.h"
 #include "test/unittests/test-utils.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class ZonePoolTest : public TestWithIsolate {
  public:
-  ZonePoolTest() : zone_pool_(isolate()) {}
+  ZonePoolTest() {}
 
  protected:
   ZonePool* zone_pool() { return &zone_pool_; }
 
   void ExpectForPool(size_t current, size_t max, size_t total) {
     ASSERT_EQ(current, zone_pool()->GetCurrentAllocatedBytes());
     ASSERT_EQ(max, zone_pool()->GetMaxAllocatedBytes());
     ASSERT_EQ(total, zone_pool()->GetTotalAllocatedBytes());
   }
 
@@ skipping 127 matching lines @@
       ExpectForPool(outer_allocated, max_loop_allocation, total_allocated);
     }
   }
   Expect(&outer_stats, 0, max_loop_allocation, total_allocated);
   ExpectForPool(0, max_loop_allocation, total_allocated);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8