Don't force eager parsing when natives are allowed.

PreParser is already capable of handling natives, because
ParseV8Intrinsic was moved to ParserBase. There's no reason to force
eager parsing when natives are allowed.

R=nikolaos@chromium.org, mstarzinger@chromium.org
BUG=v8:5398

Review-Url: https://codereview.chromium.org/2342133003
Cr-Commit-Position: refs/heads/master@{#39501}

src/parsing/parser.cc

@@ -638,7 +638,8 @@ Parser::Parser(ParseInfo* info)
   // ParseInfo during background parsing.
   DCHECK(!info->script().is_null() || info->source_stream() != nullptr ||
          info->character_stream() != nullptr);
-  set_allow_lazy(info->allow_lazy_parsing());
+  set_allow_lazy(FLAG_lazy && info->allow_lazy_parsing() &&
+                 !info->is_native() && info->extension() == nullptr);
   set_allow_natives(FLAG_allow_natives_syntax || info->is_native());
   set_allow_tailcalls(FLAG_harmony_tailcalls && !info->is_native() &&
                       info->isolate()->is_tail_call_elimination_enabled());
@@ -753,8 +754,7 @@ FunctionLiteral* Parser::DoParseProgram(ParseInfo* info) {
   DCHECK_NULL(scope_state_);
   DCHECK_NULL(target_stack_);
 
-  Mode parsing_mode = FLAG_lazy && allow_lazy() ? PARSE_LAZILY : PARSE_EAGERLY;
-  if (allow_natives() || extension_ != NULL) parsing_mode = PARSE_EAGERLY;
+  Mode parsing_mode = allow_lazy() ? PARSE_LAZILY : PARSE_EAGERLY;
 
   FunctionLiteral* result = NULL;
   {
@@ -2946,8 +2946,7 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
   // - For asm.js functions the body needs to be available when module
   //   validation is active, because we examine the entire module at once.
   bool use_temp_zone =
-      !is_lazily_parsed && FLAG_lazy && !allow_natives() &&
-      extension_ == NULL && allow_lazy() &&
+      !is_lazily_parsed && allow_lazy() &&
       function_type == FunctionLiteral::kDeclaration &&
       eager_compile_hint != FunctionLiteral::kShouldEagerCompile &&
       !(FLAG_validate_asm && scope()->IsAsmModule());