Make RecreateLayer() order the old layer above the new layer

ui/aura/window_unittest.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 "ui/aura/window.h"
 
 #include <utility>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 2039 matching lines @@
 
   scoped_ptr<ui::Layer> old_layer(w.RecreateLayer());
   layer = w.layer();
   EXPECT_EQ(ui::LAYER_SOLID_COLOR, layer->type());
   EXPECT_FALSE(layer->scale_content());
   EXPECT_FALSE(layer->visible());
   EXPECT_EQ(1u, layer->children().size());
   EXPECT_TRUE(layer->GetMasksToBounds());
 }
 
+// Verify that RecreateLayer() stacks the old layer above the newly creatd
+// layer.
+TEST_F(WindowTest, RecreateLayerZOrder) {
+  scoped_ptr<Window> w(
+      CreateTestWindow(SK_ColorWHITE, 1, gfx::Rect(0, 0, 100, 100),
+                       root_window()));
+  scoped_ptr<ui::Layer> old_layer(w->RecreateLayer());
+
+  const std::vector<ui::Layer*>& child_layers =
+      root_window()->layer()->children();
+  ASSERT_EQ(2u, child_layers.size());
+  EXPECT_EQ(w->layer(), child_layers[0]);
+  EXPECT_EQ(old_layer.get(), child_layers[1]);
+}
+
 // Ensure that acquiring a layer then recreating a layer does not crash
 // and that RecreateLayer returns null.
 TEST_F(WindowTest, AcquireThenRecreateLayer) {
   scoped_ptr<Window> w(
       CreateTestWindow(SK_ColorWHITE, 1, gfx::Rect(0, 0, 100, 100),
                        root_window()));
   scoped_ptr<ui::Layer>acquired_layer(w->AcquireLayer());
   scoped_ptr<ui::Layer>doubly_acquired_layer(w->RecreateLayer());
   EXPECT_EQ(NULL, doubly_acquired_layer.get());
 
@@ skipping 947 matching lines @@
     o.ValidateState(index++, params);
 
     w1.reset();
     w2.reset();
   }
 
 }
 
 }  // namespace test
 }  // namespace aura