move remaining uses of scanner literals into scanner

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index 8865c505bf61a8b9b0a897af7518e1b1e92734d5..bd10db3d016749653d7b88faefe4f7593e3d051f 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -1164,14 +1164,7 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
       reserved_error_loc = scanner()->location();
     }
 
-    int prev_value;
-    if (scanner()->is_literal_one_byte()) {
-      prev_value = duplicate_finder.AddAsciiSymbol(
-          scanner()->literal_one_byte_string(), 1);
-    } else {
-      prev_value =
-          duplicate_finder.AddUtf16Symbol(scanner()->literal_utf16_string(), 1);
-    }
+    int prev_value = scanner()->FindSymbol(&duplicate_finder, 1);
 
     if (!dupe_error_loc.IsValid() && prev_value != 0) {
       dupe_error_loc = scanner()->location();
@@ -1273,12 +1266,7 @@ PreParser::Expression PreParser::ParseV8Intrinsic(bool* ok) {
 
 
 void PreParser::LogSymbol() {
-  int identifier_pos = position();
-  if (scanner()->is_literal_one_byte()) {
-    log_->LogAsciiSymbol(identifier_pos, scanner()->literal_one_byte_string());
-  } else {
-    log_->LogUtf16Symbol(identifier_pos, scanner()->literal_utf16_string());
-  }
+  scanner()->LogSymbol(log_, position());
 }