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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_ACCESSIBILITY_AX_ACTION_HANDLER_BASE_H_
#define UI_ACCESSIBILITY_AX_ACTION_HANDLER_BASE_H_
#include "ui/accessibility/ax_base_export.h"
#include "ui/accessibility/ax_tree_id.h"
namespace ui {
struct AXActionData;
// Classes that host an accessibility tree in the browser process that also wish
// to become visible to accessibility clients (e.g. for relaying targets to
// source accessibility trees), can subclass this class. However, unless you
// need to have more control over how |tree_id_| is set, most classes will want
// to inherit from AXActionHandler instead, which manages it automatically.
//
// Subclasses can use |tree_id| when annotating their |AXNodeData| for clients
// to respond with the appropriate target node id.
class AX_BASE_EXPORT AXActionHandlerBase {
public:
virtual ~AXActionHandlerBase();
// Handle an action from an accessibility client.
virtual void PerformAction(const AXActionData& data) = 0;
// Returns whether this handler expects points in pixels (true) or dips
// (false) for data passed to |PerformAction|.
virtual bool RequiresPerformActionPointInPixels() const;
// A tree id appropriate for annotating events sent to an accessibility
// client.
const AXTreeID& ax_tree_id() const { return tree_id_; }
protected:
// Initializes the AXActionHandlerBase subclass with AXTreeIDUnknown().
AXActionHandlerBase();
// Initializes the AXActionHandlerBase subclass with |ax_tree_id|. It is Ok to
// pass AXTreeIDUnknown() and then call SetAXTreeID() at a later point.
explicit AXActionHandlerBase(const AXTreeID& ax_tree_id);
void SetAXTreeID(AXTreeID new_ax_tree_id);
void RemoveAXTreeID();
private:
// Register or unregister this class with |AXActionHandlerRegistry|.
void UpdateActiveState(bool active);
// Manually set in this base class, but automatically set by instances of the
// subclass AXActionHandler, which most classes inherit from.
AXTreeID tree_id_;
};
} // namespace ui
#endif // UI_ACCESSIBILITY_AX_ACTION_HANDLER_BASE_H_
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