AAPT2: Add support for comments in R.java

Change-Id: Iaa5f3b75bf7de9dbf458fa5c452f7312989f4c4f
diff --git a/tools/aapt2/util/Util.h b/tools/aapt2/util/Util.h
index 402147d..fd3fbb4 100644
--- a/tools/aapt2/util/Util.h
+++ b/tools/aapt2/util/Util.h
@@ -62,6 +62,8 @@
  */
 StringPiece16 trimWhitespace(const StringPiece16& str);
 
+StringPiece trimWhitespace(const StringPiece& str);
+
 /**
  * UTF-16 isspace(). It basically checks for lower range characters that are
  * whitespace.