Fix bug when the scanner does a pushback at the end of input.

src/scanner.cc

Index: src/scanner.cc
diff --git a/src/scanner.cc b/src/scanner.cc
index 7fd6ef22e7b7537fcc6400ea892a9f46c06f46d4..b66d10b9882c982d99398e28cf2de785e3a1d7ce 100755
--- a/src/scanner.cc
+++ b/src/scanner.cc
@@ -48,14 +48,18 @@ BufferedUC16CharacterStream::BufferedUC16CharacterStream()
 
 BufferedUC16CharacterStream::~BufferedUC16CharacterStream() { }
 
-void BufferedUC16CharacterStream::PushBack(uc16 character) {
+void BufferedUC16CharacterStream::PushBack(uc32 character) {
+  if (character == kEndOfInput) {
+    pos_--;
+    return;
+  }
   if (pushback_limit_ == NULL && buffer_cursor_ > buffer_) {
     // buffer_ is writable, buffer_cursor_ is const pointer.
-    buffer_[--buffer_cursor_ - buffer_] = character;
+    buffer_[--buffer_cursor_ - buffer_] = static_cast<uc16>(character);
     pos_--;
     return;
   }
-  SlowPushBack(character);
+  SlowPushBack(static_cast<uc16>(character));
 }