Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_window_animation.h

Index: content/browser/web_contents/aura/overscroll_window_animation.h
diff --git a/content/browser/web_contents/aura/overscroll_window_animation.h b/content/browser/web_contents/aura/overscroll_window_animation.h
new file mode 100644
index 0000000000000000000000000000000000000000..4d56e0709d4a6fbcd4d98ca25bad34001d251bb5
--- /dev/null
+++ b/content/browser/web_contents/aura/overscroll_window_animation.h
@@ -0,0 +1,106 @@
+// 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 "content/browser/renderer_host/overscroll_controller_delegate.h"
+#include "content/common/content_export.h"
+#include "ui/compositor/layer_animation_observer.h"
+
+namespace ui {
+class LayerAnimator;
+}
+
+namespace content {
+
+// Manages the animations during an overscroll navigation by handling overscroll
+// events.
+class CONTENT_EXPORT OverscrollWindowAnimation : ui::ImplicitAnimationObserver,
+                                                 OverscrollControllerDelegate {
+ public:
+  enum Direction { FORWARD, BACKWARD, NONE };
+
+  // Delegate class that interfaces with the window animation, responsible for
+  // navigation.
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // Creates an OverscrollWindow if it does not exist, or adds a new layer if
+    // it does. Returns the navigation direction.
+    virtual Direction StartNavigation(OverscrollMode mode) = 0;
+
+    // Sets the transform on the OverscrollWindow, which can set it in the
+    // active layer or the overscroll window.
+    virtual void SetTransform(const gfx::Transform& transform) = 0;
+
+    // Returns the active layer animator.
+    virtual ui::LayerAnimator* GetAnimator() = 0;
+
+    // Returns the bounds of the contents window.
+    virtual gfx::Rect GetContentsBounds() const = 0;
+
+    // Called when the animation has been completed. The delagate can then
+    // dismiss the overlay window, or wait for the page to load first.
+    virtual void OnAnimationCompleted() = 0;

[mfomitchev, 2015/02/19 19:04:59]

OnOverscrollCompleted
Maybe OnOverscrollCompleted(scoped_ptr<ui::Layer> layer) (or
OverscrollLayerWrapper instead of the Layer)

[Nina, 2015/02/27 19:32:51]

I think passing the layer instead of the wrapper makes more sense for this case.
But as we discussed, it might be OK to not pass the layer. I'll look into this
again as I code more of ONO.

+
+    // Called when we know the animation is going to complete. This should start
+    // the navigation.
+    virtual void OnAnimationCompleting() = 0;
+  };
+
+  OverscrollWindowAnimation(Delegate* delegate);
+
+  ~OverscrollWindowAnimation() override;
+
+  // Aborts all current running animations.
+  void AbortAllAnimations();
+
+  // Returns true if there is a slide animation currently in progress.
+  bool IsSlideInProgress() const;
+
+  // Overridden 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();
+
+  // Starts the overscroll cancelled animation.
+  void CancelOverscroll();
+
+  // Moves the animated window according to the given scroll deltas. Returns
+  // true if the update moved the window.
+  bool UpdateForScroll(float delta_x);
+
+  // Returns a translation for the given overscroll.
+  gfx::Vector2dF GetTranslationForOverscroll(float delta_x);
+
+  // Overridden from ui::ImplicitAnimationObserver:
+  void OnImplicitAnimationsCompleted() override;
+
+  // Delegate that provides images and handles navigation.
+  Delegate* delegate_;
+
+  // The current overscroll direction.
+  Direction direction_;
+
+  // True if the overscroll gesture has been cancelled.
+  bool overscroll_cancelled_;

[mfomitchev, 2015/02/19 19:04:59]

DOesn't seem like you need this

[Nina, 2015/02/27 19:32:51]

Removed.

+
+  // True if the overscroll animation has been completed.
+  bool animation_completed_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_ANIMATION_H_