[gtk+] gl renderer: Fix hidpi fallback rendering

[Alexander Larsson <alexl src gnome org>]

commit 9e12fc7853cfadc43fe0523a9502704335e8e079
Author: Alexander Larsson <alexl redhat com>
Date:   Sun Mar 19 19:24:50 2017 +0100

    gl renderer: Fix hidpi fallback rendering
    
    When allocating the surface, take scale into consideration.

 gsk/gskglrenderer.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/gsk/gskglrenderer.c b/gsk/gskglrenderer.c
index 6b75ff1..deeabbc 100644
--- a/gsk/gskglrenderer.c
+++ b/gsk/gskglrenderer.c
@@ -779,8 +779,9 @@ gsk_gl_renderer_add_render_item (GskGLRenderer           *self,
         cairo_t *cr;
 
         surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
-                                              ceil (node->bounds.size.width),
-                                              ceil (node->bounds.size.height));
+                                              item.size.width,
+                                              item.size.height);
+        cairo_surface_set_device_scale (surface, scale_factor, scale_factor);
         cr = cairo_create (surface);
         cairo_translate (cr, -node->bounds.origin.x, -node->bounds.origin.y);