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// Copyright (c) 2012 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.
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/optional.h"
#include "content/browser/renderer_host/overscroll_controller.h"
#include "content/common/content_export.h"
#include "ui/gfx/geometry/size.h"
namespace content {
// The delegate receives overscroll gesture updates from the controller and
// should perform appropriate actions. The delegate can optionally cap the
// overscroll deltas maintained and reported by the controller.
class CONTENT_EXPORT OverscrollControllerDelegate {
OverscrollControllerDelegate() {}
virtual ~OverscrollControllerDelegate() {}
// Get the size of the display containing the view corresponding to the
// delegate.
virtual gfx::Size GetDisplaySize() const = 0;
// This is called for each update in the overscroll amount. Returns true if
// the delegate consumed the event.
virtual bool OnOverscrollUpdate(float delta_x, float delta_y) = 0;
// This is called when the overscroll completes.
virtual void OnOverscrollComplete(OverscrollMode overscroll_mode) = 0;
// This is called when the direction of the overscroll changes. When a new
// overscroll is started (i.e. when |new_mode| is not equal to
// OVERSCROLL_NONE), |source| will be set to the device that triggered the
// overscroll gesture. |behavior| is the value of overscroll-behavior CSS
// property for the root element.
virtual void OnOverscrollModeChange(OverscrollMode old_mode,
OverscrollMode new_mode,
OverscrollSource source,
cc::OverscrollBehavior behavior) = 0;
// Returns the optional maximum amount allowed for the absolute value of
// overscroll delta corresponding to the current overscroll mode.
virtual base::Optional<float> GetMaxOverscrollDelta() const = 0;
} // namespace content