athena: Add support for fling-scroll in overview mode.

ui/events/fling_curve.h

+// Copyright 2014 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_EVENTS_FLING_CURVE_H_

[sky, 2014/08/05 17:53:36]

As this is gesture related would it make sense to move this to
ui/events/gestures?

[sadrul, 2014/08/05 18:09:06]

Yep. Done.

+#define UI_EVENTS_FLING_CURVE_H_
+
+#include "base/time/time.h"
+#include "ui/events/events_base_export.h"
+#include "ui/gfx/geometry/point_f.h"
+#include "ui/gfx/geometry/vector2d_f.h"
+
+namespace ui {
+
+class EVENTS_BASE_EXPORT FlingCurve {

[sky, 2014/08/05 17:53:36]

Add a description.

[sadrul, 2014/08/05 18:09:06]

Done.

+ public:
+  FlingCurve(const gfx::Vector2dF& velocity, base::TimeTicks start_timestamp);
+  ~FlingCurve();
+
+  gfx::Vector2dF GetScrollAmountAtTime(base::TimeTicks current_timestamp);
+  base::TimeTicks creation_time() const { return start_timestamp_; }

[sky, 2014/08/05 17:53:37]

nit: style guide says getter and field should match. So, either name this
start_timestamp() or rename start_timestamp_ to creation_time_.

[sadrul, 2014/08/05 18:09:06]

Done (changed to start_timestamp()).

+
+ private:
+  const float curve_duration_;
+
+  gfx::Vector2dF displacement_ratio_;
+  gfx::Vector2dF cumulative_scroll_;
+  base::TimeTicks start_timestamp_;

[sky, 2014/08/05 17:53:37]

const?

[sadrul, 2014/08/05 18:09:06]

Done.

+  base::TimeTicks last_timestamp_;
+  float time_offset_;
+  float position_offset_;
+
+  DISALLOW_COPY_AND_ASSIGN(FlingCurve);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_FLING_CURVE_H_