Revert of Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/window_slider.h

+// Copyright (c) 2013 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_WINDOW_SLIDER_H_
+#define CONTENT_BROWSER_WEB_CONTENTS_AURA_WINDOW_SLIDER_H_
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/common/content_export.h"
+#include "ui/aura/window_observer.h"
+#include "ui/compositor/layer_animator.h"
+#include "ui/events/event_handler.h"
+
+namespace ui {
+class Layer;
+}
+
+namespace content {
+
+class ShadowLayerDelegate;
+
+// A class for sliding the layer in a Window on top of other layers.
+class CONTENT_EXPORT WindowSlider : public ui::EventHandler,
+                                    public aura::WindowObserver {
+ public:
+  class CONTENT_EXPORT Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // Creates a layer to show behind the window-layer. Called when the
+    // window-layer starts sliding out to reveal the layer underneath.
+    // The WindowSlider takes ownership of the created layer.
+    virtual ui::Layer* CreateBackLayer() = 0;
+
+    // Creates a layer to show on top of the window-layer. Called when the new
+    // layer needs to start sliding in on top of the window-layer.
+    // The WindowSlider takes ownership of the created layer.
+    virtual ui::Layer* CreateFrontLayer() = 0;
+
+    // Called when the slide is aborted. Note that when the slide is aborted,
+    // the WindowSlider resets any transform it applied on the window-layer.
+    virtual void OnWindowSlideAborted() = 0;
+
+    // Called when the slide is about to be complete. The delegate can take
+    // action with the assumption that slide will complete soon (within the
+    // duration of the final transition animation effect).
+    // This callback is always preceeded by CreateBackLayer() or by
+    // CreateFrontLayer() callback, and is guaranteed to be followed by the
+    // OnWindowSlideCompleted() callback.
+    virtual void OnWindowSlideCompleting() = 0;
+
+    // Called when the window slide completes. Note that at the end the
+    // window-layer may have been transformed. The callback here should reset
+    // the transform if necessary. |layer| is the slider's layer (previously
+    // created via CreateBackLayer() or CreateFrontLayer()).
+    virtual void OnWindowSlideCompleted(scoped_ptr<ui::Layer> layer) = 0;
+
+    // Called when the slider is destroyed.
+    virtual void OnWindowSliderDestroyed() = 0;
+  };
+
+  // The WindowSlider slides the layers in the |owner| window. It starts
+  // intercepting scroll events on |event_window|, and uses those events to
+  // control the layer-slide. The lifetime of the slider is managed by the
+  // lifetime of |owner|, i.e. if |owner| is destroyed, then the slider also
+  // destroys itself.
+  WindowSlider(Delegate* delegate,
+               aura::Window* event_window,
+               aura::Window* owner);
+
+  ~WindowSlider() override;
+
+  // Changes the owner of the slider.
+  void ChangeOwner(aura::Window* new_owner);
+
+  bool IsSlideInProgress() const;
+
+ private:
+  // Sets up the slider layer correctly (sets the correct bounds of the layer,
+  // parents it to the right layer, and sets up the correct stacking order).
+  void SetupSliderLayer();
+
+  void UpdateForScroll(float x_offset, float y_offset);
+
+  // Completes or resets the slide depending on whether the sliding layer
+  // passed the "complete slide threshold".
+  void CompleteOrResetSlide();
+
+  // Stops all slider-owned animations, progressing them to their end-points.
+  // Note that depending on the sate of the Delegate and the WindowSlider, this
+  // may destroy the WindowSlider through animation callbacks.
+  void CompleteActiveAnimations();
+
+  // Resets in-progress slide if any, and starts the animation of the slidden
+  // window to its original position.
+  void ResetSlide();
+
+  // The following callbacks are triggered after an animation.
+  void SlideAnimationCompleted(scoped_ptr<ui::Layer> layer,
+                               scoped_ptr<ShadowLayerDelegate> shadow);
+
+  void ResetSlideAnimationCompleted(scoped_ptr<ui::Layer> layer,
+                                    scoped_ptr<ShadowLayerDelegate> shadow);
+
+  // Overridden from ui::EventHandler:
+  void OnKeyEvent(ui::KeyEvent* event) override;
+  void OnMouseEvent(ui::MouseEvent* event) override;
+  void OnScrollEvent(ui::ScrollEvent* event) override;
+  void OnGestureEvent(ui::GestureEvent* event) override;
+
+  // Overridden from aura::WindowObserver:
+  void OnWindowRemovingFromRootWindow(aura::Window* window,
+                                      aura::Window* new_root) override;
+
+  Delegate* delegate_;
+
+  // The slider intercepts scroll events from this window. The slider does not
+  // own |event_window_|. If |event_window_| is destroyed, then the slider stops
+  // listening for events, but it doesn't destroy itself.
+  aura::Window* event_window_;
+
+  // The window the slider operates on. The lifetime of the slider is bound to
+  // this window (i.e. if |owner_| does, the slider destroys itself). The slider
+  // can also delete itself when a slide gesture is completed. This does not
+  // destroy |owner_|.
+  aura::Window* owner_;
+
+  // Set to the Animator of the currently active animation. If no animation is
+  // active, this is set to NULL.
+  ui::LayerAnimator* active_animator_;
+
+  // The accumulated amount of horizontal scroll.
+  float delta_x_;
+
+  // This keeps track of the layer created by the delegate.
+  scoped_ptr<ui::Layer> slider_;
+
+  // This manages the shadow for the layers.
+  scoped_ptr<ShadowLayerDelegate> shadow_;
+
+  float active_start_threshold_;
+
+  const float start_threshold_touchscreen_;
+  const float start_threshold_touchpad_;
+  const float complete_threshold_;
+
+  base::WeakPtrFactory<WindowSlider> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowSlider);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_WINDOW_SLIDER_H_