Simplify AST ID generation.

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index 27a7b9ed4bc706a04e7bed2e9b2e90bf8448924f..847d2c2935ef9905daf17fed6796e7a9aabc9e66 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -116,12 +116,13 @@ PreParser::PreParseResult PreParser::PreParseLazyFunction(
   log_ = log;
   // Lazy functions always have trivial outer scopes (no with/catch scopes).
   PreParserScope top_scope(scope_, GLOBAL_SCOPE);
-  FunctionState top_state(&function_state_, &scope_, &top_scope, NULL,
-                          this->ast_value_factory());
+  PreParserFactory top_factory(NULL, NULL, NULL);
+  FunctionState top_state(&function_state_, &scope_, &top_scope, &top_factory);
   scope_->SetStrictMode(strict_mode);
   PreParserScope function_scope(scope_, FUNCTION_SCOPE);
-  FunctionState function_state(&function_state_, &scope_, &function_scope, NULL,
-                               this->ast_value_factory());
+  PreParserFactory function_factory(NULL, NULL, NULL);
+  FunctionState function_state(&function_state_, &scope_, &function_scope,
+                               &function_factory);
   function_state.set_is_generator(is_generator);
   DCHECK_EQ(Token::LBRACE, scanner()->current_token());
   bool ok = true;
@@ -824,8 +825,9 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   // Parse function body.
   ScopeType outer_scope_type = scope_->type();
   PreParserScope function_scope(scope_, FUNCTION_SCOPE);
-  FunctionState function_state(&function_state_, &scope_, &function_scope, NULL,
-                               this->ast_value_factory());
+  PreParserFactory factory(NULL, NULL, NULL);
+  FunctionState function_state(&function_state_, &scope_, &function_scope,
+                               &factory);
   function_state.set_is_generator(IsGeneratorFunction(kind));
   //  FormalParameterList ::
   //    '(' (Identifier)*[','] ')'