Consolidate content fling implementations

ui/gfx/android/scroller.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_GFX_ANDROID_SCROLLER_H_
-#define UI_GFX_ANDROID_SCROLLER_H_
-
-#include "base/time/time.h"
-#include "ui/gfx/gfx_export.h"
-
-namespace gfx {
-
-// Native port of android.widget.Scroller.
-// * Change-Id: I4365946f890a76fcfa78ca9d69f2a8e0848095a9
-// * Please update the Change-Id as upstream Android changes are pulled.
-class GFX_EXPORT Scroller {
- public:
-  struct Config {
-    Config();
-
-    // Controls fling deceleration. Defaults to 0.015f.
-    float fling_friction;
-
-    // Controls fling accumulation. Defaults to disabled.
-    bool flywheel_enabled;
-  };
-
-  explicit Scroller(const Config& config);
-  ~Scroller();
-
-  // Start scrolling by providing a starting point and the distance to travel.
-  // The default value of 250 milliseconds will be used for the duration.
-  void StartScroll(float start_x,
-                   float start_y,
-                   float dx,
-                   float dy,
-                   base::TimeTicks start_time);
-
-  // Start scrolling by providing a starting point, the distance to travel,
-  // and the duration of the scroll.
-  void StartScroll(float start_x,
-                   float start_y,
-                   float dx,
-                   float dy,
-                   base::TimeTicks start_time,
-                   base::TimeDelta duration);
-
-  // Start scrolling based on a fling gesture. The distance travelled will
-  // depend on the initial velocity of the fling.
-  void Fling(float start_x,
-             float start_y,
-             float velocity_x,
-             float velocity_y,
-             float min_x,
-             float max_x,
-             float min_y,
-             float max_y,
-             base::TimeTicks start_time);
-
-  // Call this when you want to know the new location.  If it returns true,
-  // the animation is not yet finished.
-  bool ComputeScrollOffset(base::TimeTicks time);
-
-  // Extend the scroll animation by |extend|. This allows a running animation
-  // to scroll further and longer when used with |SetFinalX()| or |SetFinalY()|.
-  void ExtendDuration(base::TimeDelta extend);
-  void SetFinalX(float new_x);
-  void SetFinalY(float new_y);
-
-  // Stops the animation. Contrary to |ForceFinished()|, aborting the animation
-  // causes the scroller to move to the final x and y position.
-  void AbortAnimation();
-
-  // Terminate the scroll without affecting the current x and y positions.
-  void ForceFinished(bool finished);
-
-  // Returns whether the scroller has finished scrolling.
-  bool IsFinished() const;
-
-  // Returns the time elapsed since the beginning of the scrolling.
-  base::TimeDelta GetTimePassed() const;
-
-  // Returns how long the scroll event will take.
-  base::TimeDelta GetDuration() const;
-
-  float GetStartX() const;
-  float GetStartY() const;
-  float GetCurrX() const;
-  float GetCurrY() const;
-  float GetCurrVelocity() const;
-  float GetCurrVelocityX() const;
-  float GetCurrVelocityY() const;
-  float GetFinalX() const;
-  float GetFinalY() const;
-
-  bool IsScrollingInDirection(float xvel, float yvel) const;
-
- private:
-  enum Mode {
-    UNDEFINED,
-    SCROLL_MODE,
-    FLING_MODE,
-  };
-
-  void OnDurationChanged();
-  void RecomputeDeltas();
-
-  double GetSplineDeceleration(float velocity) const;
-  base::TimeDelta GetSplineFlingDuration(float velocity) const;
-  double GetSplineFlingDistance(float velocity) const;
-
-  Mode mode_;
-
-  float start_x_;
-  float start_y_;
-  float final_x_;
-  float final_y_;
-
-  float min_x_;
-  float max_x_;
-  float min_y_;
-  float max_y_;
-
-  float curr_x_;
-  float curr_y_;
-  base::TimeTicks start_time_;
-  base::TimeTicks curr_time_;
-  base::TimeDelta duration_;
-  double duration_seconds_reciprocal_;
-  float delta_x_;
-  float delta_x_norm_;
-  float delta_y_;
-  float delta_y_norm_;
-  bool finished_;
-  bool flywheel_enabled_;
-
-  float velocity_;
-  float curr_velocity_;
-  float distance_;
-
-  float fling_friction_;
-  float deceleration_;
-  float tuning_coeff_;
-};
-
-}  // namespace gfx
-
-#endif  // UI_GFX_ANDROID_SCROLLER_H_