content/public/test/accessibility_notification_waiter.h

// Copyright 2013 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_PUBLIC_TEST_ACCESSIBILITY_NOTIFICATION_WAITER_H_
#define CONTENT_PUBLIC_TEST_ACCESSIBILITY_NOTIFICATION_WAITER_H_

#include <memory>

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "content/public/browser/web_contents_observer.h"
#include "ui/accessibility/ax_event_generator.h"
#include "ui/accessibility/ax_mode.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/accessibility/ax_tree.h"

namespace base {
class RunLoop;
}

namespace content {

class BrowserAccessibilityDelegate;
class RenderFrameHostImpl;
class WebContents;

// Create an instance of this class *before* doing any operation that
// might generate an accessibility event (like a page navigation or
// clicking on a button). Then call WaitForNotification
// afterwards to block until the specified accessibility notification has been
// received.
class AccessibilityNotificationWaiter : public WebContentsObserver {
 public:
  explicit AccessibilityNotificationWaiter(WebContents* web_contents);
  AccessibilityNotificationWaiter(WebContents* web_contents,
                                  ui::AXMode accessibility_mode,
                                  ax::mojom::Event event);
  AccessibilityNotificationWaiter(WebContents* web_contents,
                                  ui::AXMode accessibility_mode,
                                  ui::AXEventGenerator::Event event);
  ~AccessibilityNotificationWaiter() override;

  // Blocks until the specific accessibility notification registered in
  // AccessibilityNotificationWaiter is received. Ignores notifications for
  // "about:blank".
  void WaitForNotification();

  // Blocks until the notification is received, or the given timeout passes.
  void WaitForNotificationWithTimeout(base::TimeDelta timeout);

  // After WaitForNotification has returned, this will retrieve
  // the tree of accessibility nodes received from the renderer process.
  const ui::AXTree& GetAXTree() const;

  // After WaitForNotification returns, use this to retrieve the id of the
  // node that was the target of the event.
  int event_target_id() const { return event_target_id_; }

  // After WaitForNotification returns, use this to retrieve the
  // RenderFrameHostImpl that was the target of the event.
  RenderFrameHostImpl* event_render_frame_host() const {
    return event_render_frame_host_;
  }

  // WebContentsObserver override:
  void RenderFrameHostChanged(RenderFrameHost* old_host,
                              RenderFrameHost* new_host) override;

  // Quits listening and unblocks WaitForNotification* calls.
  void Quit();

 private:
  // Listen to all frames within the frame tree of this WebContents.
  void ListenToAllFrames(WebContents* web_contents);

  // Called when iterating over guest web contents so we can listen to
  // all frames within guests.
  bool ListenToGuestWebContents(WebContents* web_contents);

  // Bind either the OnAccessibilityEvent or OnGeneratedEvent callback
  // for a given frame within the WebContent's frame tree.
  void ListenToFrame(RenderFrameHostImpl* frame_host);

  // Helper to bind the OnAccessibilityEvent callback
  void BindOnAccessibilityEvent(RenderFrameHostImpl* frame_host);

  // Helper to bind the OnGeneratedEvent callback
  void BindOnGeneratedEvent(RenderFrameHostImpl* frame_host);

  // Callback from RenderViewHostImpl.
  void OnAccessibilityEvent(RenderFrameHostImpl* rfhi,
                            ax::mojom::Event event,
                            int event_target_id);

  // Callback from BrowserAccessibilityManager for all generated events.
  void OnGeneratedEvent(BrowserAccessibilityDelegate* delegate,
                        ui::AXEventGenerator::Event event,
                        int event_target_id);

  // Callback from BrowserAccessibilityManager for the focus changed event.
  //
  // TODO(982776): Remove this method once we migrate to using AXEventGenerator
  // for focus changed events.
  void OnFocusChanged();

  // Helper function to determine if the accessibility tree in
  // GetAXTree() is about the page with the url "about:blank".
  bool IsAboutBlank();

  base::Optional<ax::mojom::Event> event_to_wait_for_;
  base::Optional<ui::AXEventGenerator::Event> generated_event_to_wait_for_;
  std::unique_ptr<base::RunLoop> loop_runner_;
  int event_target_id_ = 0;
  RenderFrameHostImpl* event_render_frame_host_ = nullptr;

  base::WeakPtrFactory<AccessibilityNotificationWaiter> weak_factory_{this};

  DISALLOW_COPY_AND_ASSIGN(AccessibilityNotificationWaiter);
};

}  // namespace content

#endif  // CONTENT_PUBLIC_TEST_ACCESSIBILITY_NOTIFICATION_WAITER_H_