[metacity] frames: use CAIRO_CONTENT_COLOR for cache surface

[Alberts Muktupāvels <muktupavels src gnome org>]

commit d7a58a51357c3d6a6f9e83cb877da98af5d8a03c
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Apr 16 16:36:06 2016 +0300

    frames: use CAIRO_CONTENT_COLOR for cache surface

 src/ui/frames.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/ui/frames.c b/src/ui/frames.c
index ad6a8e7..be51bf5 100644
--- a/src/ui/frames.c
+++ b/src/ui/frames.c
@@ -2184,7 +2184,7 @@ generate_pixmap (MetaFrames            *frames,
     return NULL;
 
   result = gdk_window_create_similar_surface (frame->window,
-                                              CAIRO_CONTENT_COLOR_ALPHA,
+                                              CAIRO_CONTENT_COLOR,
                                               rect->width, rect->height);
 
   cr = cairo_create (result);