[gtk+] button: Ensure the button is "left" when a gesture is cancelled

[Carlos Garnacho <carlosg src gnome org>]

commit a4e0de183967d51f5ef7ec602f96ad6c33456701
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Feb 25 20:29:22 2015 +0100

    button: Ensure the button is "left" when a gesture is cancelled
    
    This prevents from stale widget states if the gesture happens to be
    cancelled mid-press.

 gtk/gtkbutton.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkbutton.c b/gtk/gtkbutton.c
index 9e0ca78..bb90daf 100644
--- a/gtk/gtkbutton.c
+++ b/gtk/gtkbutton.c
@@ -147,6 +147,8 @@ static void gtk_button_state_changed   (GtkWidget             *widget,
                                        GtkStateType           previous_state);
 static void gtk_button_grab_notify     (GtkWidget             *widget,
                                        gboolean               was_grabbed);
+static void gtk_button_do_release      (GtkButton             *button,
+                                        gboolean               emit_clicked);
 
 static void gtk_button_actionable_iface_init     (GtkActionableInterface *iface);
 static void gtk_button_activatable_interface_init(GtkActivatableIface  *iface);
@@ -645,6 +647,14 @@ multipress_gesture_update_cb (GtkGesture       *gesture,
 }
 
 static void
+multipress_gesture_cancel_cb (GtkGesture       *gesture,
+                              GdkEventSequence *sequence,
+                              GtkButton        *button)
+{
+  gtk_button_do_release (button, FALSE);
+}
+
+static void
 gtk_button_init (GtkButton *button)
 {
   GtkButtonPrivate *priv;
@@ -683,6 +693,7 @@ gtk_button_init (GtkButton *button)
   g_signal_connect (priv->gesture, "pressed", G_CALLBACK (multipress_pressed_cb), button);
   g_signal_connect (priv->gesture, "released", G_CALLBACK (multipress_released_cb), button);
   g_signal_connect (priv->gesture, "update", G_CALLBACK (multipress_gesture_update_cb), button);
+  g_signal_connect (priv->gesture, "cancel", G_CALLBACK (multipress_gesture_cancel_cb), button);
   gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (priv->gesture), GTK_PHASE_BUBBLE);
 }