Make cairo_set_font_size() a wrapper of cairo_set_font_matrix()

cairo_set_font_size() should be equivalent to setting the font matrix
to an appropriate scale matrix.

Implementing it this way saves some code and makes sure that the same
code path is used whenever the font matrix is changed.

src/cairo-gstate-private.h

@@ -302,10 +302,6 @@ _cairo_gstate_select_font_face (cairo_gstate_t *gstate,
 				cairo_font_slant_t slant,
 				cairo_font_weight_t weight);
 
-cairo_private cairo_status_t
-_cairo_gstate_set_font_size (cairo_gstate_t *gstate,
-			     double          size);
-
 cairo_private void
 _cairo_gstate_get_font_matrix (cairo_gstate_t *gstate,
 			       cairo_matrix_t *matrix);

src/cairo-gstate.c

@@ -1604,17 +1604,6 @@ _cairo_gstate_select_font_face (cairo_gstate_t       *gstate,
     return status;
 }
 
-cairo_status_t
-_cairo_gstate_set_font_size (cairo_gstate_t *gstate,
-			     double          size)
-{
-    _cairo_gstate_unset_scaled_font (gstate);
-
-    cairo_matrix_init_scale (&gstate->font_matrix, size, size);
-
-    return CAIRO_STATUS_SUCCESS;
-}
-
 cairo_status_t
 _cairo_gstate_set_font_matrix (cairo_gstate_t	    *gstate,
 			       const cairo_matrix_t *matrix)

src/cairo.c

@@ -3061,14 +3061,11 @@ cairo_get_font_face (cairo_t *cr)
 void
 cairo_set_font_size (cairo_t *cr, double size)
 {
-    cairo_status_t status;
+    cairo_matrix_t scale;
 
-    if (unlikely (cr->status))
-	return;
+    cairo_matrix_init_scale (&scale, size, size);
 
-    status = _cairo_gstate_set_font_size (cr->gstate, size);
-    if (unlikely (status))
-	_cairo_set_error (cr, status);
+    cairo_set_font_matrix (cr, &scale);
 }
 slim_hidden_def (cairo_set_font_size);