Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_window_animation.h

+// Copyright (c) 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_WINDOW_ANIMATION_H_
+#define CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_ANIMATION_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/renderer_host/overscroll_controller.h"
+#include "content/browser/renderer_host/overscroll_controller_delegate.h"
+#include "content/browser/web_contents/aura/overscroll_navigation_overlay.h"
+#include "ui/aura/window.h"
+#include "ui/aura_extra/image_window_delegate.h"
+#include "ui/compositor/layer_animation_observer.h"
+
+namespace content {
+
+class ShadowLayerDelegate;
+class WebContentsImpl;
+
+// Manages the animations during an overscroll navigation.
+// TODO write doc and nice comment explaining how overscroll navigation works.
+class OverscrollWindowAnimation : ui::ImplicitAnimationObserver,
+                                  OverscrollControllerDelegate {
+ public:
+  OverscrollWindowAnimation(WebContentsImpl* web_contents,
+                            OverscrollNavigationOverlay* ono,
+                            aura::Window* web_contents_window);
+
+  ~OverscrollWindowAnimation() override;
+
+  // Cancels the current animation.
+  void CancelAnimation();
+
+  // Moves the animated window according to the given scroll deltas. Returns
+  // true if the update moved the window.
+  bool UpdateForScroll(float delta_x);
+
+  // Aborts all current running animations.
+  void AbortAllAnimations();
+
+  // Dismisses the overlay.
+  void DismissOverlay();
+
+  // Returns the overscroll window delegate as an ImageWindowDelegate.
+  aura_extra::ImageWindowDelegate* delegate() {
+    return static_cast<aura_extra::ImageWindowDelegate*>(
+        overscroll_window_->delegate());
+  }
+
+  // Overridden from ui::ImplicitAnimationObserver:
+  void OnImplicitAnimationsCompleted() override;
+
+  // Overridn from OverscrollControllerDelegate:
+  gfx::Rect GetVisibleBounds() const override;
+
+  bool OnOverscrollUpdate(float delta_x, float delta_y) override;
+
+  void OnOverscrollComplete(OverscrollMode overscroll_mode) override;
+
+  void OnOverscrollModeChange(OverscrollMode old_mode,
+                              OverscrollMode new_mode) override;
+
+ private:
+  // Prepares the overscroll window to begin animating.
+  void StartAnimating();
+
+  // Adds a new layer on top of the overscroll window.
+  void AddNewLayer();
+
+  // Stops the animation, dismissing the overscroll window.
+  void FadeOutOverscrollWindow();
+
+  // Returns the bounds for the overscroll current direction and RTL status.
+  gfx::Rect GetStarterBounds() const;
+
+  // Returns the window that should be animated for the overscroll navigation.
+  aura::Window* GetWindowToAnimateForOverscroll() const;
+
+  gfx::Vector2dF GetTranslationForOverscroll(float delta_x);
+
+  // The window shown on top of the live window for the animations.
+  scoped_ptr<aura::Window> overscroll_window_;
+
+  // Shadow shown under the animated window.
+  scoped_ptr<ShadowLayerDelegate> overscroll_shadow_;
+
+  // Web contents that this instance refers to.
+  WebContentsImpl* web_contents_;
+
+  // Reference to the navigation overlay.
+  OverscrollNavigationOverlay* ono_;
+
+  // The current overscroll direction.
+  OverscrollNavigationOverlay::Direction direction_;
+
+  // Window that hosts the web contents.
+  aura::Window* web_contents_window_;
+
+  // Sliding layer used during second stage overscroll navigation.
+  // TODO it is very likely that we don't need to own this layer.
+  scoped_ptr<ui::Layer> slide_layer_;
+
+  // TODO rename and make the following fields behave better.
+  // Indicates if we should fade out the overlay prior to destroying it.
+  bool fade_out_;
+
+  // Indicates if the overscroll gesture has been cancelled.
+  bool animation_cancelled_;
+
+  // Indicates if the overscroll gesture has been completed.
+  bool gesture_completed_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_ANIMATION_H_