add unit tests for MediaGalleriesDialogGtk

chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc

Index: chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc
diff --git a/chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc b/chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc
index 108bed196dd50cc55ac92646ed0e421125cf91f5..16fbec63a6b0f3a17daeda5022787bce7c689cdb 100644
--- a/chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc
+++ b/chrome/browser/ui/gtk/extensions/media_galleries_dialog_gtk.cc
@@ -26,7 +26,10 @@ MediaGalleriesDialogGtk::MediaGalleriesDialogGtk(
         ignore_toggles_(false),
         accepted_(false) {
   InitWidgets();
-  window_ = new ConstrainedWindowGtk(controller->tab_contents(), this);
+
+  // May be NULL during tests.
+  if (controller->tab_contents())
+    window_ = new ConstrainedWindowGtk(controller->tab_contents(), this);
 }
 
 MediaGalleriesDialogGtk::~MediaGalleriesDialogGtk() {
@@ -124,7 +127,8 @@ void MediaGalleriesDialogGtk::DeleteDelegate() {
 }
 
 void MediaGalleriesDialogGtk::OnToggled(GtkWidget* widget) {
-  gtk_widget_set_sensitive(confirm_, TRUE);
+  if (confirm_)
+    gtk_widget_set_sensitive(confirm_, TRUE);
 
   if (ignore_toggles_)
     return;