Reorder the NativeViews attached to a view via kViewHostKey according to the position of the view

chrome/browser/ui/views/dropdown_bar_host_aura.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/views/dropdown_bar_host.h"
 
 #include "base/logging.h"
+#include "chrome/browser/ui/views/frame/browser_view.h"
 #include "ui/aura/window.h"
 #include "ui/base/events/event.h"
+#include "ui/views/view.h"
+#include "ui/views/view_constants_aura.h"
 #include "ui/views/widget/widget.h"
 
 using content::NativeWebKeyboardEvent;
 using content::WebContents;
 
 NativeWebKeyboardEvent DropdownBarHost::GetKeyboardEvent(
      const WebContents* contents,
      const ui::KeyEvent& key_event) {
   // NativeWebKeyboardEvent should take a const gfx::NativeEvent, which would
   // prevent this casting.
   ui::Event* ui_event =
       static_cast<ui::Event*>(const_cast<ui::KeyEvent*>(&key_event));
   return NativeWebKeyboardEvent(ui_event);
 }
 
 void DropdownBarHost::SetWidgetPositionNative(const gfx::Rect& new_pos,
                                               bool no_redraw) {
   if (!host_->IsVisible())
     host_->GetNativeView()->Show();
   host_->GetNativeView()->SetBounds(new_pos);
+
+  if (!host_view_.get()) {
+    // Create view to denote the z-order of |host_| relative to child views of
+    // |browser_view_| which have layers and NativeViews attached to a child
+    // NativeViewHost of |browser_view_|.
+    host_view_.reset(new views::View());
+    host_view_->set_owned_by_client();
+    browser_view_->AddChildView(host_view_.get());

[sky, 2013/05/13 22:54:17]

One reason I like binding to an existing view owned by BrowserView is that the
z-order is easy to understand. When you start dynamically adding views it gets
harder to reason about. I prefer creating and binding to a long lived view in
Browserview.

+
+    // Set the mapping between the view and the NativeView. The property does
+    // not need to be cleared because |host_view_| and |host_| are both
+    // destroyed when DropdownBarHost is destroyed.
+    host_->GetNativeView()->SetProperty(views::kHostViewKey, host_view_.get());
+  }
+  browser_view_->ReorderChildView(host_view_.get(), -1);
+
+  // TODO(pkotwicz): Complete implementing denoting the z-order via
+  // aura::client::kHostViewKey and remove once the implementation is done.
   host_->StackAtTop();
 }