Add parsing for ambient declarations

src/ast/scopes.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_AST_SCOPES_H_
 #define V8_AST_SCOPES_H_
 
 #include "src/ast/ast.h"
 #include "src/hashmap.h"
 #include "src/pending-compilation-error-handler.h"
@@ skipping 303 matching lines @@
   bool is_eval_scope() const { return scope_type_ == EVAL_SCOPE; }
   bool is_function_scope() const { return scope_type_ == FUNCTION_SCOPE; }
   bool is_module_scope() const { return scope_type_ == MODULE_SCOPE; }
   bool is_script_scope() const { return scope_type_ == SCRIPT_SCOPE; }
   bool is_catch_scope() const { return scope_type_ == CATCH_SCOPE; }
   bool is_block_scope() const { return scope_type_ == BLOCK_SCOPE; }
   bool is_with_scope() const { return scope_type_ == WITH_SCOPE; }
   bool is_arrow_scope() const {
     return is_function_scope() && IsArrowFunction(function_kind_);
   }
+  bool is_toplevel_scope() const {
+    return is_script_scope() || is_eval_scope() || is_module_scope();
+  }
   bool is_declaration_scope() const { return is_declaration_scope_; }
 
   void set_is_declaration_scope() { is_declaration_scope_ = true; }
 
   // Information about which scopes calls eval.
   bool calls_eval() const { return scope_calls_eval_; }
   bool calls_sloppy_eval() const {
     return scope_calls_eval_ && is_sloppy(language_mode_);
   }
   bool outer_scope_calls_sloppy_eval() const {
@@ skipping 473 matching lines @@
   AstValueFactory* ast_value_factory_;
   Zone* zone_;
 
   PendingCompilationErrorHandler pending_error_handler_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_SCOPES_H_