[epiphany] clear-data-view: Check if cancellable is NULL before clearing it

[Michael Catanzaro <mcatanzaro src gnome org>]

commit c5d72c387d801588dd109093ca2885c8916b233a
Author: Yetizone <andreii lisita gmail com>
Date:   Wed Jul 1 11:32:44 2020 +0300

    clear-data-view: Check if cancellable is NULL before clearing it
    
    Needed to prevent crashing in case clear_data_view_dispose() is called multiple times

 src/preferences/clear-data-view.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/preferences/clear-data-view.c b/src/preferences/clear-data-view.c
index 45ec63d1c..47dabd685 100644
--- a/src/preferences/clear-data-view.c
+++ b/src/preferences/clear-data-view.c
@@ -338,8 +338,10 @@ clear_data_view_dispose (GObject *object)
 {
   ClearDataView *clear_data_view = (ClearDataView *)object;
 
-  g_cancellable_cancel (clear_data_view->cancellable);
-  g_clear_object (&clear_data_view->cancellable);
+  if (clear_data_view->cancellable) {
+    g_cancellable_cancel (clear_data_view->cancellable);
+    g_clear_object (&clear_data_view->cancellable);
+  }
 
   G_OBJECT_CLASS (clear_data_view_parent_class)->dispose (object);
 }