GTK: More raw struct access removal, this time focusing on GtkDialog.

chrome/browser/ui/gtk/task_manager_gtk.cc

Index: chrome/browser/ui/gtk/task_manager_gtk.cc
diff --git a/chrome/browser/ui/gtk/task_manager_gtk.cc b/chrome/browser/ui/gtk/task_manager_gtk.cc
index 55f5456bf8d4b9cc4ba278b05f2ff8550e885e0d..eef7039b708d4d1b9f8cbbe8790009f8f68cb243 100644
--- a/chrome/browser/ui/gtk/task_manager_gtk.cc
+++ b/chrome/browser/ui/gtk/task_manager_gtk.cc
@@ -499,13 +499,13 @@ void TaskManagerGtk::Init() {
 
   // Setting the link widget to secondary positions the button on the left side
   // of the action area (vice versa for RTL layout).
-  gtk_button_box_set_child_secondary(
-      GTK_BUTTON_BOX(GTK_DIALOG(dialog_)->action_area), link, TRUE);
+  GtkWidget* action_area = gtk_dialog_get_action_area(GTK_DIALOG(dialog_));
+  gtk_button_box_set_child_secondary(GTK_BUTTON_BOX(action_area), link, TRUE);
 
   ConnectAccelerators();
 
-  gtk_box_set_spacing(GTK_BOX(GTK_DIALOG(dialog_)->vbox),
-                      ui::kContentAreaSpacing);
+  GtkWidget* content_area = gtk_dialog_get_content_area(GTK_DIALOG(dialog_));
+  gtk_box_set_spacing(GTK_BOX(content_area), ui::kContentAreaSpacing);
 
   destroy_handler_id_ = g_signal_connect(dialog_, "destroy",
                                          G_CALLBACK(OnDestroyThunk), this);