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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef ASH_ASSISTANT_UI_BASE_ASSISTANT_SCROLL_VIEW_H_
#define ASH_ASSISTANT_UI_BASE_ASSISTANT_SCROLL_VIEW_H_
#include "base/component_export.h"
#include "base/memory/raw_ptr.h"
#include "base/observer_list.h"
#include "base/scoped_observation.h"
#include "ui/base/metadata/metadata_header_macros.h"
#include "ui/views/controls/scroll_view.h"
#include "ui/views/view_observer.h"
namespace ash {
class COMPONENT_EXPORT(ASSISTANT_UI) AssistantScrollView
: public views::ScrollView,
public views::ViewObserver {
METADATA_HEADER(AssistantScrollView, views::ScrollView)
public:
class Observer : public base::CheckedObserver {
public:
// Invoked when the scrollable contents' preferred size has changed.
virtual void OnContentsPreferredSizeChanged(views::View* content_view) {}
protected:
Observer() = default;
~Observer() override = default;
};
AssistantScrollView();
AssistantScrollView(const AssistantScrollView&) = delete;
AssistantScrollView& operator=(const AssistantScrollView) = delete;
~AssistantScrollView() override;
// views::ViewObserver:
void OnViewPreferredSizeChanged(views::View* view) override;
// Adds/removes the specified |observer|.
void AddScrollViewObserver(Observer* observer);
void RemoveScrollViewObserver(Observer* observer);
views::View* content_view() { return content_view_observation_.GetSource(); }
const views::View* content_view() const {
return content_view_observation_.GetSource();
}
private:
void InitLayout();
base::ObserverList<Observer> observers_;
// The observed view is owned by the view hierarchy. This could be a raw_ptr
// to the view + ScopedObservation, but accessing the view through the
// ScopedObservation saves a pointer.
base::ScopedObservation<views::View, views::ViewObserver>
content_view_observation_{this};
};
} // namespace ash
#endif // ASH_ASSISTANT_UI_BASE_ASSISTANT_SCROLL_VIEW_H_
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