[gnome-control-center/wip/carlosg/wacom-test-button-sensitivity] wacom: Update "Test your settings" button sensitivity on device availability

[Carlos Garnacho <carlosg src gnome org>]

commit 903cc8b114f627c5df003ca1ae60bbb7538f9283
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Feb 11 19:16:45 2019 +0100

    wacom: Update "Test your settings" button sensitivity on device availability
    
    The button/popover are meaningless if there's no device to test with. Set
    it inactive (so the popover hides if visible) and set insensitive if no
    devices are found.

 panels/wacom/cc-wacom-panel.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
---
diff --git a/panels/wacom/cc-wacom-panel.c b/panels/wacom/cc-wacom-panel.c
index 72c8c46a0..b1f7bad7a 100644
--- a/panels/wacom/cc-wacom-panel.c
+++ b/panels/wacom/cc-wacom-panel.c
@@ -52,6 +52,7 @@ struct _CcWacomPanel
        GtkWidget        *stylus_notebook;
        GtkWidget        *test_popover;
        GtkWidget        *test_draw_area;
+       GtkWidget        *test_button;
        GHashTable       *devices; /* key=GsdDevice, value=CcWacomDevice */
        GHashTable       *pages; /* key=device name, value=GtkWidget */
        GHashTable       *stylus_pages; /* key=CcWacomTool, value=GtkWidget */
@@ -336,6 +337,20 @@ add_stylus (CcWacomPanel *self,
        return TRUE;
 }
 
+static void
+update_test_button (CcWacomPanel *self)
+{
+       if (!self->test_button)
+               return;
+
+       if (g_hash_table_size (self->devices) == 0) {
+               gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (self->test_button), FALSE);
+               gtk_widget_set_sensitive (self->test_button, FALSE);
+       } else {
+               gtk_widget_set_sensitive (self->test_button, TRUE);
+       }
+}
+
 static void
 update_current_tool (CcWacomPanel  *panel,
                     GdkDevice     *device,
@@ -468,6 +483,9 @@ cc_wacom_panel_constructed (GObject *object)
 
        g_signal_connect_object (shell, "event",
                                 G_CALLBACK (on_shell_event_cb), self, 0);
+
+       self->test_button = button;
+       update_test_button (self);
 }
 
 static const char *
@@ -603,6 +621,8 @@ update_current_page (CcWacomPanel  *self,
                if (num_pages > 1)
                        gtk_notebook_set_current_page (GTK_NOTEBOOK (self->tablet_notebook), 1);
        }
+
+       update_test_button (self);
 }
 
 static void