Index: ui/compositor/layer_owner.h |
diff --git a/ui/compositor/layer_owner.h b/ui/compositor/layer_owner.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..898e7b02026f953d339d9b0ba44e7183d35aee07 |
--- /dev/null |
+++ b/ui/compositor/layer_owner.h |
@@ -0,0 +1,47 @@ |
+// 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. |
+ |
+#ifndef UI_COMPOSITOR_LAYER_OWNER_H_ |
+#define UI_COMPOSITOR_LAYER_OWNER_H_ |
+#pragma once |
+ |
+#include "base/compiler_specific.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "ui/compositor/compositor_export.h" |
+#include "ui/compositor/layer.h" |
+ |
+namespace ui { |
+ |
+class COMPOSITOR_EXPORT LayerOwner { |
+ public: |
+ LayerOwner(); |
+ virtual ~LayerOwner(); |
+ |
+ // Releases the owning reference to its layer, and returns it. |
+ // This is used when you need to animate the presentation of the owner just |
+ // prior to destroying it. The Owner can be destroyed soon after calling this |
+ // function, and the caller is then responsible for disposing of the layer |
+ // once any animation completes. Note that layer() will remain valid until the |
+ // end of ~LayerOwner(). |
+ Layer* AcquireLayer() WARN_UNUSED_RESULT; |
+ |
+ ui::Layer* layer() { return layer_; } |
+ const ui::Layer* layer() const { return layer_; } |
+ |
+ protected: |
+ // The LayerOwner owns its layer unless ownership is relinquished via a call |
+ // to AcquireLayer(). After that moment |layer_| will still be valid but |
+ // |layer_owner_| will be NULL. The reason for releasing ownership is that |
+ // the client may wish to animate the layer beyond the lifetime of the owner, |
+ // e.g. fading it out when it is destroyed. |
+ scoped_ptr<Layer> layer_owner_; |
+ Layer* layer_; |
+ |
+ private: |
+ DISALLOW_COPY_AND_ASSIGN(LayerOwner); |
+}; |
+ |
+} // namespace ui |
+ |
+#endif // UI_COMPOSITOR_LAYER_OWNER_H_ |