Deserialize the scope chain for background parsing jobs on the main thread

src/parsing/parser.cc

 // 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.
 
 #include "src/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 753 matching lines @@
     info->set_ast_value_factory(new AstValueFactory(zone(), info->hash_seed()));
     info->set_ast_value_factory_owned();
     ast_value_factory_ = info->ast_value_factory();
     ast_node_factory_.set_ast_value_factory(ast_value_factory_);
   }
 }
 
 void Parser::DeserializeScopeChain(
     ParseInfo* info, Handle<Context> context,
     Scope::DeserializationMode deserialization_mode) {
+  DCHECK(ThreadId::Current().Equals(info->isolate()->thread_id()));
   // TODO(wingo): Add an outer SCRIPT_SCOPE corresponding to the native
   // context, which will have the "this" binding for script scopes.
   DeclarationScope* script_scope = NewScriptScope();
   info->set_script_scope(script_scope);
   Scope* scope = script_scope;
   if (!context.is_null() && !context->IsNativeContext()) {
     scope = Scope::DeserializeScopeChain(info->isolate(), zone(), *context,
                                          script_scope, ast_value_factory(),
                                          deserialization_mode);
     if (info->context().is_null()) {
@@ skipping 6149 matching lines @@
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8