content/common/media/media_devices.mojom

// Copyright 2016 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.

module mojom;

import "media/capture/mojo/video_capture_types.mojom";

[Native]
enum MediaDeviceType;

[Native]
struct MediaDeviceInfo;

// The values for this enum match the ones defined in
// https://w3c.github.io/mediacapture-main/#def-constraint-facingMode
// with the addition of NONE, which would map to the empty string in
// JavaScript.
enum FacingMode {
  NONE,
  USER,
  ENVIRONMENT,
  LEFT,
  RIGHT
};

struct VideoInputDeviceCapabilities {
  string device_id;
  array<media.mojom.VideoCaptureFormat> formats;
  FacingMode facing_mode;
};

// This object lives in the browser and is responsible for processing device
// enumeration requests and managing subscriptions for device-change
// notifications.
interface MediaDevicesDispatcherHost {
  // The reply always contains NUM_MEDIA_DEVICE_TYPES elements.
  // The result is indexed by device type as defined in 
  // content/common/media/media_devices.h.
  EnumerateDevices(bool request_audio_input,
                   bool request_video_input,
                   bool request_audio_output)
                       => (array<array<MediaDeviceInfo>> enumeration);
  
  // Returns a list of video devices and their capabilities.
  // If there is a user-preferred device, it is the first in the result.
  // The result of this function is intended for the implementation details
  // of algorithms such as settings selection for getUserMedia.
  // Do not expose the data contained in result of this function to JavaScript.
  GetVideoInputCapabilities()
      => (array<VideoInputDeviceCapabilities> video_input_device_capabilities);

  // Creates a subscription for device-change notifications for the calling
  // frame/security origin. It is the responsibility of the caller to send
  // |subscription_id| values that are unique per device type.
  // Requests to create a subscription with an ID that already exists for type
  // |type| are invalid and result in a renderer crash.
  SubscribeDeviceChangeNotifications(MediaDeviceType type,
                                     uint32 subscription_id);

  // Removes a subscription to device-change notifications for the calling
  // frame. The caller is responsible for sending |subscription_id| values that
  // that refer to existing subscriptions for type |type|. Requests to remove
  // a nonexisting subscription with are invalid and result in a renderer crash.
  UnsubscribeDeviceChangeNotifications(MediaDeviceType type,
                                       uint32 subscription_id);
};

// This object lives in the renderer process and is used by the browser process
// to pass device-change notifications to the renderer.
interface MediaDevicesListener {
  // Called to notify a change in the set of devices of type |type| for
  // subscription |subscription_id|. |device_infos| contains the new list of
  // devices of type |type|, with device and group IDs obfuscated according to
  // the subscription's security origin.
  OnDevicesChanged(MediaDeviceType type,
                   uint32 subscription_id,
                   array<MediaDeviceInfo> device_infos);
};