Simplify scanner and generate better error message for legacy octals in templates

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 3b221ac09235654af5ff7fe241b6a507e6839df7..44cd0b74f9dfd280bdc2e21614d06b8b8b82cbf4 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -2846,6 +2846,7 @@ ParserBase<Traits>::ParseTemplateLiteral(ExpressionT tag, int start, bool* ok) {
   if (peek() == Token::TEMPLATE_TAIL) {
     Consume(Token::TEMPLATE_TAIL);
     int pos = position();
+    CheckOctalLiteral(pos, peek_position(), CHECK_OK);

[arv (Not doing code reviews), 2014/12/18 20:38:51]

CheckOctalLiteral needs to be updated to use a different error message.

[caitp (gmail), 2014/12/18 20:44:18]

Yeah --- I was undecided whether it should be something generic like "Octal
escape sequences are deprecated", or let callers pass in their own message ID
and make a template-specific error message.

What do you think?

[arv (Not doing code reviews), 2014/12/18 20:46:58]

I think a new error message would be best.

[caitp (gmail), 2014/12/18 21:09:50]

Done and done

     typename Traits::TemplateLiteralState ts = Traits::OpenTemplateLiteral(pos);
     Traits::AddTemplateSpan(&ts, true);
     return Traits::CloseTemplateLiteral(&ts, start, tag);
@@ -2897,6 +2898,7 @@ ParserBase<Traits>::ParseTemplateLiteral(ExpressionT tag, int start, bool* ok) {
   } while (next == Token::TEMPLATE_SPAN);
 
   DCHECK_EQ(next, Token::TEMPLATE_TAIL);
+  CheckOctalLiteral(pos, peek_position(), CHECK_OK);
   // Once we've reached a TEMPLATE_TAIL, we can close the TemplateLiteral.
   return Traits::CloseTemplateLiteral(&ts, start, tag);
 }