Refactor Parser to make it usable on a background thread.

src/preparser.h

 // Copyright 2012 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_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/func-name-inferrer.h"
@@ skipping 60 matching lines @@
              AstNode::IdGen* ast_node_id_gen,
              typename Traits::Type::Parser this_object)
       : Traits(this_object),
         parenthesized_function_(false),
         scope_(NULL),
         function_state_(NULL),
         extension_(extension),
         fni_(NULL),
         log_(log),
         mode_(PARSE_EAGERLY),  // Lazy mode must be set explicitly.
+        stack_limit_(stack_limit),
         scanner_(scanner),
-        stack_limit_(stack_limit),
         stack_overflow_(false),
         allow_lazy_(false),
         allow_natives_syntax_(false),
         allow_generators_(false),
         allow_arrow_functions_(false),
         zone_(zone),
         ast_node_id_gen_(ast_node_id_gen) {}
 
   // Getters that indicate whether certain syntactical constructs are
   // allowed to be parsed by this instance of the parser.
@@ skipping 469 matching lines @@
   // Heuristically that means that the function will be called immediately,
   // so never lazily compile it.
   bool parenthesized_function_;
 
   typename Traits::Type::Scope* scope_;  // Scope stack.
   FunctionState* function_state_;  // Function state stack.
   v8::Extension* extension_;
   FuncNameInferrer* fni_;
   ParserRecorder* log_;
   Mode mode_;
+  uintptr_t stack_limit_;
 
  private:
   Scanner* scanner_;
-  uintptr_t stack_limit_;
   bool stack_overflow_;
 
   bool allow_lazy_;
   bool allow_natives_syntax_;
   bool allow_generators_;
   bool allow_arrow_functions_;
 
   typename Traits::Type::Zone* zone_;  // Only used by Parser.
   AstNode::IdGen* ast_node_id_gen_;
 };
@@ skipping 2075 matching lines @@
       DCHECK(IsAccessorAccessorConflict(old_type, type));
       // Both accessors of the same type.
       parser()->ReportMessage("accessor_get_set");
     }
     *ok = false;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H