minui: graphics: add ability to query font size

Change-Id: I5e8f477b7b205794f2975f12e6b6010c177f6052
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/minui/graphics.c b/minui/graphics.c
index b79631a..57ca810 100644
--- a/minui/graphics.c
+++ b/minui/graphics.c
@@ -201,6 +201,12 @@
     return gr_font->cwidth * strlen(s);
 }
 
+void gr_font_size(int *x, int *y)
+{
+    *x = gr_font->cwidth;
+    *y = gr_font->cheight;
+}
+
 int gr_text(int x, int y, const char *s)
 {
     GGLContext *gl = gr_context;