add globbing util function

experimental/skpdiff/skpdiff_util.h

Index: experimental/skpdiff/skpdiff_util.h
diff --git a/experimental/skpdiff/skpdiff_util.h b/experimental/skpdiff/skpdiff_util.h
index 34fa8f3e0082196113b8349e24c33adf471dc626..d98175e038bf2fb0f791721346b3338816ea55e7 100644
--- a/experimental/skpdiff/skpdiff_util.h
+++ b/experimental/skpdiff/skpdiff_util.h
@@ -34,5 +34,13 @@ double get_seconds();
  */
 bool get_directory(const char path[], SkTArray<SkString>* entries);
 
+/**
+ * Gets the files that match the specified pattern in sorted order.
+ * @param  globPattern The pattern to use. Patterns must be valid paths, optionally with wildcards (*)
+ * @param  entries     An array to return the results into
+ * @return             True on success, false otherwise
+ */
+bool glob_files(const char globPattern[], SkTArray<SkString>* entries);
+
 
 #endif