[gtksourceview] completion: remove use of deprecated API

[Christian Hergert <chergert src gnome org>]

commit 80eaf1c4c59f70b40cf04ce19602cdc417d2dfed
Author: Christian Hergert <chergert redhat com>
Date:   Thu Apr 25 20:48:40 2019 -0700

    completion: remove use of deprecated API
    
    This removes the use of deprecated GdkScreen API in favor of the new
    GdkMonitor API. This required bumping to 3.22, which should be enough
    in the general case to prepare for 4.x.

 gtksourceview/gtksourcecompletion.c          | 14 +++++++++-----
 gtksourceview/gtksourcecompletioncontainer.c | 10 +++++++---
 gtksourceview/gtksourcecompletioninfo.c      | 22 ++++++++++++----------
 3 files changed, 28 insertions(+), 18 deletions(-)
---
diff --git a/gtksourceview/gtksourcecompletion.c b/gtksourceview/gtksourcecompletion.c
index c91f91e6..fedbe29d 100644
--- a/gtksourceview/gtksourcecompletion.c
+++ b/gtksourceview/gtksourcecompletion.c
@@ -742,21 +742,25 @@ gtk_source_completion_activate_proposal (GtkSourceCompletion *completion)
 static void
 update_info_position (GtkSourceCompletion *completion)
 {
-       GdkScreen *screen;
+       GdkDisplay *display;
+       GdkMonitor *monitor;
+       GdkWindow *window;
+       GdkRectangle geom;
        gint x, y;
        gint width, height;
-       gint screen_width;
        gint info_width;
 
        gtk_window_get_position (GTK_WINDOW (completion->priv->main_window), &x, &y);
        gtk_window_get_size (GTK_WINDOW (completion->priv->main_window), &width, &height);
        gtk_window_get_size (GTK_WINDOW (completion->priv->info_window), &info_width, NULL);
 
-       screen = gtk_window_get_screen (GTK_WINDOW (completion->priv->main_window));
-       screen_width = gdk_screen_get_width (screen);
+       display = gtk_widget_get_display (GTK_WIDGET (completion->priv->main_window));
+       window = gtk_widget_get_window (GTK_WIDGET (completion->priv->main_window));
+       monitor = gdk_display_get_monitor_at_window (display, window);
+       gdk_monitor_get_geometry (monitor, &geom);
 
        /* Determine on which side to place it */
-       if (x + width + info_width >= screen_width)
+       if (x + width + info_width >= geom.width)
        {
                x -= info_width;
        }
diff --git a/gtksourceview/gtksourcecompletioncontainer.c b/gtksourceview/gtksourcecompletioncontainer.c
index 5a01986a..06a90a3d 100644
--- a/gtksourceview/gtksourcecompletioncontainer.c
+++ b/gtksourceview/gtksourcecompletioncontainer.c
@@ -47,18 +47,22 @@ get_max_width (GtkSourceCompletionContainer *container)
 {
        if (gtk_widget_get_realized (GTK_WIDGET (container)))
        {
+               GdkDisplay *display;
+               GdkMonitor *monitor;
                GtkWidget *toplevel;
                GdkWindow *window;
-               GdkScreen *screen;
+               GdkRectangle geom;
                gint max_width;
                gint xorigin;
 
                toplevel = gtk_widget_get_toplevel (GTK_WIDGET (container));
                window = gtk_widget_get_window (toplevel);
-               screen = gdk_window_get_screen (window);
+               display = gtk_widget_get_display (toplevel);
+               monitor = gdk_display_get_monitor_at_window (display, window);
+               gdk_monitor_get_geometry (monitor, &geom);
 
                gdk_window_get_origin (window, &xorigin, NULL);
-               max_width = gdk_screen_get_width (screen) - xorigin;
+               max_width = geom.width - xorigin;
 
                return MAX (max_width, UNREALIZED_WIDTH);
        }
diff --git a/gtksourceview/gtksourcecompletioninfo.c b/gtksourceview/gtksourcecompletioninfo.c
index 4315132a..957d6a5c 100644
--- a/gtksourceview/gtksourcecompletioninfo.c
+++ b/gtksourceview/gtksourcecompletioninfo.c
@@ -461,19 +461,21 @@ move_to_iter (GtkSourceCompletionInfo *window,
              GtkTextView             *view,
              GtkTextIter             *iter)
 {
-       GdkScreen *screen;
+       GdkDisplay *display;
+       GdkWindow *gdk_window;
+       GdkMonitor *monitor;
+       GdkRectangle geom;
        gint x, y;
        gint w, h;
-       gint sw, sh;
        gint cx, cy;
        gint oy;
        gint height;
        gboolean overlapup;
 
-       screen = gtk_window_get_screen (GTK_WINDOW (window));
-
-       sw = gdk_screen_get_width (screen);
-       sh = gdk_screen_get_height (screen);
+       display = gtk_widget_get_display (GTK_WIDGET (view));
+       gdk_window = gtk_widget_get_window (GTK_WIDGET (view));
+       monitor = gdk_display_get_monitor_at_window (display, gdk_window);
+       gdk_monitor_get_geometry (monitor, &geom);
 
        get_iter_pos (view, iter, &x, &y, &height);
        gtk_window_get_size (GTK_WINDOW (window), &w, &h);
@@ -484,18 +486,18 @@ move_to_iter (GtkSourceCompletionInfo *window,
        compensate_for_gravity (window, &cx, &cy, w, h);
 
        /* Push window inside screen */
-       if (x - cx + w > sw)
+       if (x - cx + w > geom.width)
        {
-               x = (sw - w) + cx;
+               x = (geom.width - w) + cx;
        }
        else if (x - cx < 0)
        {
                x = cx;
        }
 
-       if (y - cy + h > sh)
+       if (y - cy + h > geom.height)
        {
-               y = (sh - h) + cy;
+               y = (geom.height - h) + cy;
                overlapup = TRUE;
        }
        else if (y - cy < 0)