CCA: Run getUserMedia() once before enumerateDevices()

Recently the spec is updated to require a successful getUserMedia()
before running enumerateDevices(). Otherwise the deviceId and label
fields would be empty. See https://crbug.com/1101860 for more details.

Bug: 1103303, 1101860
Test: tast run <nocturne> camera.CCAUI*

Change-Id: I61b4278d20720bf6424dada24a1d4e4b73f8c5d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2321907Reviewed-by: Wei Lee <wtlee@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792156}

chromeos/components/camera_app_ui/resources/src/js/browser_proxy/browser_proxy.js

@@ -12,6 +12,31 @@ import {BrowserProxy} from './browser_proxy_interface.js';
  * @implements {BrowserProxy}
  */
 class ChromeAppBrowserProxy {
+  /** @override */
+  async requestEnumerateDevicesPermission() {
+    // It's required to run getUserMedia() successfully once before running
+    // enumerateDevices(). Otherwise the deviceId and label fields would be
+    // empty. See https://crbug.com/1101860 for more details.
+    const doGetUserMedia = async (constraints) => {
+      try {
+        const stream = await navigator.mediaDevices.getUserMedia(constraints);
+        stream.getTracks().forEach((track) => track.stop());
+        return true;
+      } catch (e) {
+        return false;
+      }
+    };
+    // Try audio stream first since it's usually much faster to open an audio
+    // stream than a video stream. Note that in some form factors such as
+    // Chromebox there might be no internal microphone, so the audio request
+    // might fail and we would fall back to video. If no external camera
+    // connected in that case, the video request might also fail and we need to
+    // try again later.
+    return (
+        await doGetUserMedia({audio: true}) ||
+        await doGetUserMedia({video: true}));
+  }
+
   /** @override */
   async getExternalDir() {
     let volumes;

chromeos/components/camera_app_ui/resources/src/js/browser_proxy/browser_proxy_interface.js

@@ -13,6 +13,12 @@ import {
  * @interface
  */
 export class BrowserProxy {
+  /**
+   * @return {!Promise<boolean>}
+   * @abstract
+   */
+  async requestEnumerateDevicesPermission() {}
+
   /**
    * @return {!Promise<?AbstractDirectoryEntry>}
    * @abstract

chromeos/components/camera_app_ui/resources/src/js/browser_proxy/webui_browser_proxy.js

@@ -17,6 +17,13 @@ function NOTIMPLEMENTED() {
  * @implements {BrowserProxy}
  */
 class WebUIBrowserProxy {
+  /** @override */
+  async requestEnumerateDevicesPermission() {
+    // No operation here since the permission is automatically granted for
+    // the chrome:// scheme.
+    return true;
+  }
+
   /** @override */
   async getExternalDir() {
     NOTIMPLEMENTED();

chromeos/components/camera_app_ui/resources/src/js/device/device_info_updater.js

@@ -2,12 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import {browserProxy} from '../browser_proxy/browser_proxy.js';
 import {DeviceOperator} from '../mojo/device_operator.js';
 // eslint-disable-next-line no-unused-vars
 import {ResolutionList} from '../type.js';
+
 import {Camera3DeviceInfo} from './camera3_device_info.js';
-import {PhotoConstraintsPreferrer,  // eslint-disable-line no-unused-vars
-        VideoConstraintsPreferrer,  // eslint-disable-line no-unused-vars
+import {
+  PhotoConstraintsPreferrer,  // eslint-disable-line no-unused-vars
+  VideoConstraintsPreferrer,  // eslint-disable-line no-unused-vars
 } from './constraints_preferrer.js';
 import {LegacyVCDError} from './error.js';
 
@@ -62,6 +65,13 @@ export class DeviceInfoUpdater {
      */
     this.devicesInfo_ = this.enumerateDevices_();
 
+    /**
+     * Got the permission to run enumerateDevices() or not.
+     * @type {boolean}
+     * @private
+     */
+    this.canEnumerateDevices_ = false;
+
     /**
      * Camera3DeviceInfo of all available video devices. Is null on HALv1 device
      * without mojo api support.
@@ -137,6 +147,13 @@ export class DeviceInfoUpdater {
    * @private
    */
   async enumerateDevices_() {
+    if (!this.canEnumerateDevices_) {
+      this.canEnumerateDevices_ =
+          await browserProxy.requestEnumerateDevicesPermission();
+      if (!this.canEnumerateDevices_) {
+        throw new Error('Failed to get the permission for enumerateDevices()');
+      }
+    }
     const devices = (await navigator.mediaDevices.enumerateDevices())
                         .filter((device) => device.kind === 'videoinput');
     if (devices.length === 0) {
@@ -174,7 +191,7 @@ export class DeviceInfoUpdater {
    * Requests to lock update of device information. This function is preserved
    * for device information reader to lock the update capability so as to ensure
    * getting consistent data between all information providers.
-   * @param {!function(!DeviceInfoUpdater): Promise} callback Called after
+   * @param {!function(): Promise} callback Called after
    *     update capability is locked. Getting information from all providers in
    *     callback are guaranteed to be consistent.
    */
@@ -190,7 +207,7 @@ export class DeviceInfoUpdater {
     }
     this.lockingUpdate_ = (async () => {
       try {
-        await callback(this);
+        await callback();
       } finally {
         this.lockingUpdate_ = null;
       }