Disable vsync for the kiosk mode

Enabled vsync cased black screen in RHEL10 in kiosk mode. This should be
fixed in the Firefox 140 esr.

Related: RHEL-84207

disable-vsync-for-kiosk.patch

@@ -0,0 +1,18 @@
+diff -up firefox-128.8.0/widget/gtk/nsWindow.cpp.kiosk-vsync firefox-128.8.0/widget/gtk/nsWindow.cpp
+--- firefox-128.8.0/widget/gtk/nsWindow.cpp.kiosk-vsync	2025-03-13 13:04:03.112498669 +0100
++++ firefox-128.8.0/widget/gtk/nsWindow.cpp	2025-03-13 13:06:13.227823446 +0100
+@@ -6348,9 +6348,13 @@ nsresult nsWindow::Create(nsIWidget* aPa
+   // Initialize the window specific VsyncSource early in order to avoid races
+   // with BrowserParent::UpdateVsyncParentVsyncDispatcher().
+   // Only use for toplevel windows for now, see bug 1619246.
++  //
++  // Disable vsync for the kiosk mode - it cause the black screen
++  // This will be fixed in Firefox 140
+   if (GdkIsWaylandDisplay() &&
+       StaticPrefs::widget_wayland_vsync_enabled_AtStartup() &&
+-      IsTopLevelWindowType()) {
++      IsTopLevelWindowType() && 
++      !gKioskMode ) {
+     mWaylandVsyncSource = new WaylandVsyncSource(this);
+     mWaylandVsyncDispatcher = new VsyncDispatcher(mWaylandVsyncSource);
+     LOG_VSYNC("  created WaylandVsyncSource");

firefox.spec

@@ -244,6 +244,9 @@ Patch09:        rhbz-2131158-webrtc-nss-fix.patch
 Patch10:        build-ffvpx.patch
 Patch11:        build-disable-gamepad.patch
 Patch12:        firefox-system-nss-replace-xyber-with-mlkem.patch
+# Enabled vsync cause the black screen when running in Kiosk mode
+# This will be fixed in Firefox 140
+Patch13:        disable-vsync-for-kiosk.patch
 
 # -- Upstreamed patches --
 Patch51:       mozilla-bmo1170092.patch
@@ -1222,6 +1225,7 @@ echo "--------------------------------------------"
 %if 0%{?rhel} == 10
 %patch -P12 -p1 -b .system-nss-replace-xyber-with-mlkem
 %endif
+%patch -P13 -p1 -b .kiosk-vsync
 
 # We need to create the wasi.patch with the correct path to the wasm libclang_rt.
 %if %{with_wasi_sdk}