Added BTextControl::TextLength() method.

src/kits/interface/TextControl.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2012, Haiku Inc.
+ * Copyright 2001-2015, Haiku Inc.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
@@ -567,6 +567,13 @@ BTextControl::Text() const
 }
 
 
+int32
+BTextControl::TextLength() const
+{
+	return fText->TextLength();
+}
+
+
 void
 BTextControl::MarkAsInvalid(bool invalid)
 {