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

ui/views/widget/native_widget_aura.cc

Index: ui/views/widget/native_widget_aura.cc
diff --git a/ui/views/widget/native_widget_aura.cc b/ui/views/widget/native_widget_aura.cc
index 754b258eead2f0474b8189a9b147c285c587a58c..de8069c7cb28b145b7c01edf83a5f7691d3b9ecf 100644
--- a/ui/views/widget/native_widget_aura.cc
+++ b/ui/views/widget/native_widget_aura.cc
@@ -30,11 +30,13 @@
 #include "ui/native_theme/native_theme_aura.h"
 #include "ui/views/drag_utils.h"
 #include "ui/views/ime/input_method_bridge.h"
+#include "ui/views/view_constants_aura.h"
 #include "ui/views/views_delegate.h"
 #include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
 #include "ui/views/widget/drop_helper.h"
 #include "ui/views/widget/native_widget_aura_window_observer.h"
 #include "ui/views/widget/native_widget_delegate.h"
+#include "ui/views/widget/native_widget_layer_reorderer_aura.h"
 #include "ui/views/widget/root_view.h"
 #include "ui/views/widget/tooltip_manager_aura.h"
 #include "ui/views/widget/widget_aura_utils.h"
@@ -172,6 +174,9 @@ void NativeWidgetAura::InitNativeWidget(const Widget::InitParams& params) {
                        GetWidget()->widget_delegate()->CanMaximize());
   window_->SetProperty(aura::client::kCanResizeKey,
                        GetWidget()->widget_delegate()->CanResize());
+
+  layer_reorderer_.reset(new NativeWidgetLayerReordererAura(window_,
+      GetWidget()->GetRootView()));
 }
 
 NonClientFrameView* NativeWidgetAura::CreateNonClientFrameView() {
@@ -226,6 +231,21 @@ gfx::Vector2d NativeWidgetAura::CalculateOffsetToAncestorWithLayer(
   return gfx::Vector2d();
 }
 
+void NativeWidgetAura::ReorderLayers() {
+  layer_reorderer_->ReorderLayers();
+}
+
+bool NativeWidgetAura::HasNativeViewAttachedToViewTree() const {
+  // TODO(pkotwicz): Set the the kHostViewKey property when a
+  // NativeViewHost attaches a NativeView to |window_|.
+  const std::vector<aura::Window*>& child_windows = window_->children();
+  for (size_t i = 0; i < child_windows.size(); ++i) {
+    if (child_windows[i]->GetProperty(kHostViewKey))
+      return true;
+  }
+  return false;
+}
+
 void NativeWidgetAura::ViewRemoved(View* view) {
   DCHECK(drop_helper_.get() != NULL);
   drop_helper_->ResetTargetViewIfEquals(view);