Remove the dependency of Zone on Isolate

src/json-parser.h

 // Copyright 2011 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_JSON_PARSER_H_
 #define V8_JSON_PARSER_H_
 
 #include "src/v8.h"
 
 #include "src/char-predicates-inl.h"
@@ skipping 14 matching lines @@
   }
 
   static const int kEndOfString = -1;
 
  private:
   explicit JsonParser(Handle<String> source)
       : source_(source),
         source_length_(source->length()),
         isolate_(source->map()->GetHeap()->isolate()),
         factory_(isolate_->factory()),
-        zone_(isolate_),
         object_constructor_(isolate_->native_context()->object_function(),
                             isolate_),
         position_(-1) {
     source_ = String::Flatten(source_);
     pretenure_ = (source_length_ >= kPretenureTreshold) ? TENURED : NOT_TENURED;
 
     // Optimized fast case where we only have Latin1 characters.
     if (seq_one_byte) {
       seq_source_ = Handle<SeqOneByteString>::cast(source_);
     }
@@ skipping 765 matching lines @@
 
   DCHECK_EQ('"', c0_);
   // Advance past the last '"'.
   AdvanceSkipWhitespace();
   return result;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_JSON_PARSER_H_