[mutter] screen-cast: Fix monitor recording on HiDPI

[Carlos Garnacho <carlosg src gnome org>]

commit 3fa6a92cc5dda6ab3939c3e982185f6caf453360
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Jan 25 22:06:39 2019 +0100

    screen-cast: Fix monitor recording on HiDPI
    
    It scaled the logical monitor rect with scale to get the stream
    dimensions, but that is only valid when having
    'scale-monitor-framebuffers' enabled. Even when it was, it didn't work
    properly, as clutter_stage_capture_into() doesn't work properly with
    scaled monitor framebuffers yet.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/415

 src/backends/meta-screen-cast-monitor-stream-src.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/meta-screen-cast-monitor-stream-src.c 
b/src/backends/meta-screen-cast-monitor-stream-src.c
index 897b86ae6..036c573a5 100644
--- a/src/backends/meta-screen-cast-monitor-stream-src.c
+++ b/src/backends/meta-screen-cast-monitor-stream-src.c
@@ -102,7 +102,11 @@ meta_screen_cast_monitor_stream_src_get_specs (MetaScreenCastStreamSrc *src,
   logical_monitor = meta_monitor_get_logical_monitor (monitor);
   mode = meta_monitor_get_current_mode (monitor);
 
-  scale = logical_monitor->scale;
+  if (meta_is_stage_views_scaled ())
+    scale = logical_monitor->scale;
+  else
+    scale = 1.0;
+
   *width = (int) roundf (logical_monitor->rect.width * scale);
   *height = (int) roundf (logical_monitor->rect.height * scale);
   *frame_rate = meta_monitor_mode_get_refresh_rate (mode);