Fix crash/leak issue in native_view_host_gtk.cc.

views/controls/native_control_gtk.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved. Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
 #include "views/controls/native_control_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include "base/logging.h"
 #include "views/focus/focus_manager.h"
@@ skipping 31 matching lines @@
     // controls need a parent widget to function properly.
     CreateNativeControl();
   }
 }
 
 void NativeControlGtk::VisibilityChanged(View* starting_from, bool is_visible) {
   if (!is_visible) {
     if (native_view()) {
       // We destroy the child widget when we become invisible because of the
       // performance cost of maintaining widgets that aren't currently needed.
-      GtkWidget* widget = native_view();
       Detach();
-      gtk_widget_destroy(widget);
+      // Make sure that Detach destroyed the widget.
+      DCHECK(!native_view());
     }
   } else if (!native_view()) {
     if (GetWidget())
       CreateNativeControl();
   } else {
     // The view becomes visible after native control is created.
     // Layout now.
     Layout();
   }
 }
@@ skipping 24 matching lines @@
     // TODO(jcampan): http://crbug.com/21378 Reenable this NOTREACHED() when the
     // options page is only based on views.
     // NOTREACHED();
     NOTIMPLEMENTED();
     return;
   }
   focus_manager->SetFocusedView(control->focus_view());
 }
 
 }  // namespace views