Move content/renderer input handling for web input events to ui

content/renderer/input/input_scroll_elasticity_controller.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 CONTENT_RENDERER_INPUT_INPUT_SCROLL_ELASTICITY_CONTROLLER_H_
-#define CONTENT_RENDERER_INPUT_INPUT_SCROLL_ELASTICITY_CONTROLLER_H_
-
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "cc/input/scroll_elasticity_helper.h"
-#include "content/common/content_export.h"
-#include "third_party/WebKit/public/web/WebInputEvent.h"
-
-// InputScrollElasticityController is based on
-// WebKit/Source/platform/mac/ScrollElasticityController.h
-/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
- * THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-namespace cc {
-struct InputHandlerScrollResult;
-}  // namespace cc
-
-namespace content {
-
-class CONTENT_EXPORT InputScrollElasticityController {
- public:
-  explicit InputScrollElasticityController(cc::ScrollElasticityHelper* helper);
-  virtual ~InputScrollElasticityController();
-
-  base::WeakPtr<InputScrollElasticityController> GetWeakPtr();
-
-  // Update the overscroll state based a wheel event that has been processed.
-  // Note that this assumes that all events are coming from a single input
-  // device. If the user simultaneously uses multiple input devices, Cocoa may
-  // not correctly pass all the gesture begin and end events. In this case,
-  // this class may disregard some scrolls that come in at unexpected times.
-  void ObserveWheelEventAndResult(
-      const blink::WebMouseWheelEvent& wheel_event,
-      const cc::InputHandlerScrollResult& scroll_result);
-  void Animate(base::TimeTicks time);
-
-  void ReconcileStretchAndScroll();
-
- private:
-  enum State {
-    // The initial state, during which the overscroll amount is zero and
-    // there are no active or momentum scroll events coming in. This state
-    // is briefly returned to between the active and momentum phases of a
-    // scroll (if there is no overscroll).
-    kStateInactive,
-    // The state between receiving PhaseBegan/MayBegin and PhaseEnd/Cancelled,
-    // corresponding to the period during which the user has fingers on the
-    // trackpad. The overscroll amount is updated as input events are received.
-    // When PhaseEnd is received, the state transitions to Inactive if there is
-    // no overscroll and MomentumAnimated if there is non-zero overscroll.
-    kStateActiveScroll,
-    // The state between receiving a momentum PhaseBegan and PhaseEnd, while
-    // there is no overscroll. The overscroll amount is updated as input events
-    // are received. If the overscroll is ever non-zero then the state
-    // immediately transitions to kStateMomentumAnimated.
-    kStateMomentumScroll,
-    // The state while the overscroll amount is updated by an animation. If
-    // the user places fingers on the trackpad (a PhaseMayBegin is received)
-    // then the state transition to kStateActiveScroll. Otherwise the state
-    // transitions to Inactive when the overscroll amount becomes zero.
-    kStateMomentumAnimated,
-  };
-
-  void UpdateVelocity(const gfx::Vector2dF& event_delta,
-                      const base::TimeTicks& event_timestamp);
-  void Overscroll(const gfx::Vector2dF& input_delta,
-                  const gfx::Vector2dF& overscroll_delta);
-  void EnterStateMomentumAnimated(
-      const base::TimeTicks& triggering_event_timestamp);
-  void EnterStateInactive();
-
-  // Returns true if |direction| is pointing in a direction in which it is not
-  // possible to scroll any farther horizontally (or vertically). It is only in
-  // this circumstance that an overscroll in that direction may begin.
-  bool PinnedHorizontally(float direction) const;
-  bool PinnedVertically(float direction) const;
-  // Whether or not the content of the page is scrollable horizontaly (or
-  // vertically).
-  bool CanScrollHorizontally() const;
-  bool CanScrollVertically() const;
-
-  cc::ScrollElasticityHelper* helper_;
-  State state_;
-
-  // If there is no overscroll, require a minimum overscroll delta before
-  // starting the rubber-band effect. Track the amount of scrolling that has
-  // has occurred but has not yet caused rubber-band stretching in
-  // |pending_overscroll_delta_|.
-  gfx::Vector2dF pending_overscroll_delta_;
-
-  // Maintain a calculation of the velocity of the scroll, based on the input
-  // scroll delta divide by the time between input events. Track this velocity
-  // in |scroll_velocity| and the previous input event timestamp for finite
-  // differencing in |last_scroll_event_timestamp_|.
-  gfx::Vector2dF scroll_velocity;
-  base::TimeTicks last_scroll_event_timestamp_;
-
-  // The force of the rubber-band spring. This is equal to the cumulative sum
-  // of all overscroll offsets since entering a non-Inactive state. This is
-  // reset to zero only when entering the Inactive state.
-  gfx::Vector2dF stretch_scroll_force_;
-
-  // Momentum animation state. This state is valid only while the state is
-  // MomentumAnimated, and is initialized in EnterStateMomentumAnimated.
-  base::TimeTicks momentum_animation_start_time_;
-  gfx::Vector2dF momentum_animation_initial_stretch_;
-  gfx::Vector2dF momentum_animation_initial_velocity_;
-
-  // This is set in response to a scroll (most likely programmatic) occuring
-  // while animating the momentum phase. In this case, re-set the initial
-  // velocity, stretch, and start time at the next frame (this is the same
-  // behavior as would happen if the scroll were caused by an active scroll).
-  bool momentum_animation_reset_at_next_frame_;
-
-  base::WeakPtrFactory<InputScrollElasticityController> weak_factory_;
-  DISALLOW_COPY_AND_ASSIGN(InputScrollElasticityController);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_INPUT_INPUT_SCROLL_ELASTICITY_CONTROLLER_H_