gecko/gfx/cairo/text-path-filling-threshold.patch

diff --git a/gfx/cairo/cairo/src/cairo-gstate.c b/gfx/cairo/cairo/src/cairo-gstate.c
--- a/gfx/cairo/cairo/src/cairo-gstate.c
+++ b/gfx/cairo/cairo/src/cairo-gstate.c
@@ -1673,26 +1673,31 @@ _cairo_gstate_show_text_glyphs (cairo_gs
 
     source_pattern = &source_pattern_stack.base;
     status = _cairo_gstate_copy_transformed_source (gstate, &source_pattern);
     if (unlikely (status))
 	goto CLEANUP_GLYPHS;
 
     /* For really huge font sizes, we can just do path;fill instead of
      * show_glyphs, as show_glyphs would put excess pressure on the cache,
-     * and moreover, not all components below us correctly handle huge font
-     * sizes.  I wanted to set the limit at 256.  But alas, seems like cairo's
+     * not all components below us correctly handle huge font sizes, and
+     * path filling can be cheaper since parts of glyphs are likely to be
+     * clipped out.  256 seems like a good limit.  But alas, seems like cairo's
      * rasterizer is something like ten times slower than freetype's for huge
-     * sizes.  So, no win just yet.  For now, do it for insanely-huge sizes,
-     * just to make sure we don't make anyone unhappy.  When we get a really
-     * fast rasterizer in cairo, we may want to readjust this.
+     * sizes.  So, no win just yet when we're using cairo's rasterizer.
+     * For now, if we're using cairo's rasterizer, use path filling only
+     * for insanely-huge sizes, just to make sure we don't make anyone
+     * unhappy.  When we get a really fast rasterizer in cairo, we may
+     * want to readjust this.  The threshold calculation is
+     * encapsulated in _cairo_surface_get_text_path_fill_threshold.
      *
      * Needless to say, do this only if show_text_glyphs is not available. */
     if (cairo_surface_has_show_text_glyphs (gstate->target) ||
-	_cairo_scaled_font_get_max_scale (gstate->scaled_font) <= 10240) {
+	_cairo_scaled_font_get_max_scale (gstate->scaled_font) <=
+	_cairo_surface_get_text_path_fill_threshold (gstate->target)) {
 	status = _cairo_surface_show_text_glyphs (gstate->target,
 						  gstate->op,
 						  source_pattern,
 						  utf8, utf8_len,
 						  transformed_glyphs, num_glyphs,
 						  transformed_clusters, num_clusters,
 						  cluster_flags,
 						  gstate->scaled_font, NULL);
diff --git a/gfx/cairo/cairo/src/cairo-surface.c b/gfx/cairo/cairo/src/cairo-surface.c
--- a/gfx/cairo/cairo/src/cairo-surface.c
+++ b/gfx/cairo/cairo/src/cairo-surface.c
@@ -1120,16 +1120,22 @@ cairo_surface_get_fallback_resolution (c
 				       double		*y_pixels_per_inch)
 {
     if (x_pixels_per_inch)
 	*x_pixels_per_inch = surface->x_fallback_resolution;
     if (y_pixels_per_inch)
 	*y_pixels_per_inch = surface->y_fallback_resolution;
 }
 
+int
+_cairo_surface_get_text_path_fill_threshold (const cairo_surface_t *surface)
+{
+    return surface->backend->fill == NULL ? 10240 : 256;
+}
+
 cairo_bool_t
 _cairo_surface_has_device_transform (cairo_surface_t *surface)
 {
     return ! _cairo_matrix_is_identity (&surface->device_transform);
 }
 
 /**
  * _cairo_surface_acquire_source_image:
diff --git a/gfx/cairo/cairo/src/cairoint.h b/gfx/cairo/cairo/src/cairoint.h
--- a/gfx/cairo/cairo/src/cairoint.h
+++ b/gfx/cairo/cairo/src/cairoint.h
@@ -2065,16 +2065,19 @@ _cairo_surface_composite_shape_fixup_unb
 						int			    dst_x,
 						int			    dst_y,
 						unsigned int		    width,
 						unsigned int		    height);
 
 cairo_private cairo_bool_t
 _cairo_surface_is_opaque (const cairo_surface_t *surface);
 
+cairo_private int
+_cairo_surface_get_text_path_fill_threshold (const cairo_surface_t *surface);
+
 cairo_private void
 _cairo_surface_set_device_scale (cairo_surface_t *surface,
 				 double		  sx,
 				 double		  sy);
 
 cairo_private cairo_bool_t
 _cairo_surface_has_device_transform (cairo_surface_t *surface);