File mozilla-fullscreen_part_3.patch of Package MozillaFirefox

# HG changeset patch
# Parent 664cde3b388a4f852afc13eb982668d327d9a9e2
bsc#992549, merged in FF46

mozilla-release:
changeset:   316477:8e52730bd8ee
user:        Xidorn Quan <quanxunzhen@gmail.com>
date:        Tue Jan 12 15:18:47 2016 +1100
files:       widget/gtk/mozgtk/mozgtk.c widget/gtk/nsWindow.cpp
description:
Bug 1189622 part 3 - Return failure if fullscreen support is not available for the X11 desktop. r=karlt

diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
--- a/widget/gtk/mozgtk/mozgtk.c
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -122,16 +122,17 @@ STUB(gdk_x11_display_get_user_time)
 STUB(gdk_x11_display_get_xdisplay)
 STUB(gdk_x11_get_default_root_xwindow)
 STUB(gdk_x11_get_default_xdisplay)
 STUB(gdk_x11_get_server_time)
 STUB(gdk_x11_get_xatom_by_name)
 STUB(gdk_x11_get_xatom_by_name_for_display)
 STUB(gdk_x11_lookup_xdisplay)
 STUB(gdk_x11_screen_get_xscreen)
+STUB(gdk_x11_screen_supports_net_wm_hint)
 STUB(gdk_x11_visual_get_xvisual)
 STUB(gdk_x11_window_foreign_new_for_display)
 STUB(gdk_x11_window_lookup_for_display)
 STUB(gdk_x11_window_set_user_time)
 STUB(gdk_x11_xatom_to_atom)
 STUB(gtk_accel_label_new)
 STUB(gtk_alignment_get_type)
 STUB(gtk_alignment_new)
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -4985,22 +4985,39 @@ nsWindow::PerformFullscreenTransition(Fu
     auto transitionData = new FullscreenTransitionData(aStage, aDuration,
                                                        aCallback, data);
     g_timeout_add_full(G_PRIORITY_HIGH,
                        FullscreenTransitionData::sInterval,
                        FullscreenTransitionData::TimeoutCallback,
                        transitionData, nullptr);
 }
 
+static bool
+IsFullscreenSupported(GtkWidget* aShell)
+{
+#ifdef MOZ_X11
+    GdkScreen* screen = gtk_widget_get_screen(aShell);
+    GdkAtom atom = gdk_atom_intern("_NET_WM_STATE_FULLSCREEN", FALSE);
+    if (!gdk_x11_screen_supports_net_wm_hint(screen, atom)) {
+        return false;
+    }
+#endif
+    return true;
+}
+
 NS_IMETHODIMP
 nsWindow::MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen)
 {
     LOG(("nsWindow::MakeFullScreen [%p] aFullScreen %d\n",
          (void *)this, aFullScreen));
 
+    if (!IsFullscreenSupported(mShell)) {
+        return NS_ERROR_NOT_AVAILABLE;
+    }
+
     if (aFullScreen) {
         if (mSizeMode != nsSizeMode_Fullscreen)
             mLastSizeMode = mSizeMode;
 
         mSizeMode = nsSizeMode_Fullscreen;
         gtk_window_fullscreen(GTK_WINDOW(mShell));
     }
     else {