layers: Consolidate the ownership of layers in views::View and aura::Window.

ui/views/view_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 <map>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/rand_util.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
@@ skipping 3142 matching lines @@
   ASSERT_EQ(2u, parent_layer->children().size());
   EXPECT_EQ(c1->layer(), parent_layer->children()[0]);
   EXPECT_EQ(c2->layer(), parent_layer->children()[1]);
 
   // Move c1 to the front. The layers should have moved too.
   content->ReorderChildView(c1, -1);
   EXPECT_EQ(c1->layer(), parent_layer->children()[1]);
   EXPECT_EQ(c2->layer(), parent_layer->children()[0]);
 }
 
+// Verifies that the layer of a view can be acquired properly.
+TEST_F(ViewLayerTest, AcquireLayer) {
+  View* content = new View;
+  widget()->SetContentsView(content);
+  View* c1 = new View;
+  c1->SetPaintToLayer(true);
+  EXPECT_TRUE(c1->layer());
+
+  scoped_ptr<ui::Layer> layer(c1->AcquireLayer());
+  EXPECT_EQ(layer.get(), c1->layer());
+
+  layer.reset(c1->RecreateLayer());
+  EXPECT_NE(c1->layer(), layer.get());
+}
+
 #endif  // USE_AURA
 
 }  // namespace views