[polari] thumbnailer: Disable hardware acceleration

[Florian Müllner <fmuellner src gnome org>]

commit d619f098715daad24461ec15b89337141e447d3b
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Jan 8 23:58:44 2020 +0100

    thumbnailer: Disable hardware acceleration
    
    It's not useful as we aren't actually showing the window, and
    doesn't work in the flatpak anyway (because we don't poke the
    corresponding hole in the sandbox).
    
    https://gitlab.gnome.org/GNOME/polari/merge_requests/147

 src/thumbnailer.js | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/src/thumbnailer.js b/src/thumbnailer.js
index db98ba7..e2ad0a5 100644
--- a/src/thumbnailer.js
+++ b/src/thumbnailer.js
@@ -27,9 +27,14 @@ let PreviewWindow = GObject.registerClass({
 
         super._init(params);
 
+        let settings = new WebKit2.Settings({
+            hardware_acceleration_policy: WebKit2.HardwareAccelerationPolicy.NEVER,
+        });
+
         this._view = new WebKit2.WebView({
             is_ephemeral: true,
             visible: true,
+            settings,
         });
         this.add(this._view);