Remove legacy API on Utf16CharacterStream.

test/cctest/parsing/test-scanner-streams.cc

Index: test/cctest/parsing/test-scanner-streams.cc
diff --git a/test/cctest/parsing/test-scanner-streams.cc b/test/cctest/parsing/test-scanner-streams.cc
index 951e20d44bd60f50e64ed7b7c5d1c3875ed3bbd0..1bd9dbc7cded7f16fb94ab92650df8f038446ce2 100644
--- a/test/cctest/parsing/test-scanner-streams.cc
+++ b/test/cctest/parsing/test-scanner-streams.cc
@@ -184,21 +184,21 @@ void TestCharacterStream(const char* reference, i::Utf16CharacterStream* stream,
   while (i > end / 4) {
     int32_t c0 = reference[i - 1];
     CHECK_EQU(i, stream->pos());
-    stream->PushBack(c0);
+    stream->Back();
     i--;
     CHECK_EQU(i, stream->pos());
     int32_t c1 = stream->Advance();
     i++;
     CHECK_EQU(i, stream->pos());
     CHECK_EQ(c0, c1);
-    stream->PushBack(c0);
+    stream->Back();
     i--;
     CHECK_EQU(i, stream->pos());
   }
 
   // Seek + read streams one char at a time.
   unsigned halfway = end / 2;
-  stream->SeekForward(halfway - i);
+  stream->Seek(stream->pos() + halfway - i);
   for (i = halfway; i < end; i++) {
     CHECK_EQU(i, stream->pos());
     CHECK_EQU(reference[i], stream->Advance());