views: Some more layer change, and add/update some tests for layers.

views/controls/native_control_gtk.cc

Index: views/controls/native_control_gtk.cc
diff --git a/views/controls/native_control_gtk.cc b/views/controls/native_control_gtk.cc
index 965d34738c194215329ca08a25fb57a8b23bc847..1e3c0b6d0badd66f697bcf593c7d9580054fda45 100644
--- a/views/controls/native_control_gtk.cc
+++ b/views/controls/native_control_gtk.cc
@@ -172,6 +172,8 @@ void NativeControlGtk::ViewHierarchyChanged(bool is_add, View* parent,
 }
 
 void NativeControlGtk::VisibilityChanged(View* starting_from, bool is_visible) {
+  if (starting_from != this)
+    return;

[oshima, 2011/10/10 08:10:09]

I first thought this isn't correct (because you need to hide native widget when
parent view is invisible), but looking at code more closely, the code has
changed recently and Detach no longer *detach* the widget. Honestly I don't
understand why this works. Could be that we just happen to not have such use
case because there is far less native view used in the browser, but I may be
wrong. Let me talk to dave first and will get back to you.

   if (!is_visible) {
     if (native_view()) {
       // We destroy the child widget when we become invisible because of the