Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_layer_wrapper.h

+// Copyright 2015 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 CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_LAYER_WRAPPER_H_
+#define CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_LAYER_WRAPPER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/transform.h"
+
+namespace aura {
+class Window;
+}
+
+namespace ui {
+class Layer;
+class LayerAnimator;
+}
+
+namespace content {
+
+class ImageLayerDelegate;
+class ShadowLayerDelegate;
+
+// Wraps a window or a layer, exposing some of their common API to allow
+// overscroll animations for both cases.
+class OverscrollLayerWrapper {

[mfomitchev, 2015/02/27 21:33:42]

Perhaps we don't need this - perhaps OWA could always work with a layer and we
would only create a window in ONO when OWA's animation finishes

[Nina, 2015/03/09 15:54:52]

Ack, for now we decided to keep the wrapper.

+ public:
+  // The contructor takes ownership of the overscroll window.
+  OverscrollLayerWrapper();
+
+  ~OverscrollLayerWrapper();
+
+  // Wrap the given window or layer. For a given instance of
+  // OverscrollLayerWrapper, only call one of these, once.
+  void WrapWindow(aura::Window* window);

[mfomitchev, 2015/02/27 21:33:42]

Just put these into constr

[Nina, 2015/03/09 15:54:52]

Done.

+  void WrapLayer(ui::Layer* layer);
+
+  // Applies the |transform| to the wrapped target.
+  void SetTransform(const gfx::Transform& transform);
+
+  // Sets the bounds of the wrapped target.
+  void SetBounds(const gfx::Rect& bounds);
+
+  // Returns the wrapped target layer animator.
+  ui::LayerAnimator* GetAnimator();
+
+  // Returns the wrapped target layer bounds.
+  gfx::Rect GetBounds();
+
+ private:
+  // The wrapped layer.
+  ui::Layer* layer_;

[mfomitchev, 2015/02/27 21:33:42]

Perhaps make it own window/layer and have ONO/WCVA/etc own the wrapper

[Nina, 2015/03/09 15:54:52]

I would love to, but by doing that we would lose the ability to wrap the web
contents window.

+
+  // The wrapped window.
+  aura::Window* window_;
+
+  // Shadow shown under the animated layer.
+  scoped_ptr<ShadowLayerDelegate> shadow_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_LAYER_WRAPPER_H_