feat: Allow set the videoContainer in the Player constructor (#6953)

Related to
#6672 (comment)

lib/player.js

@@ -547,10 +547,12 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    *    When provided, the player will attach to <code>mediaElement</code>,
    *    similar to calling <code>attach</code>. When not provided, the player
    *    will remain detached.
+   * @param {HTMLElement=} videoContainer
+   *    The videoContainer to construct UITextDisplayer
    * @param {function(shaka.Player)=} dependencyInjector Optional callback
    *   which is called to inject mocks into the Player.  Used for testing.
    */
-  constructor(mediaElement, dependencyInjector) {
+  constructor(mediaElement, videoContainer = null, dependencyInjector) {
     super();
 
     /** @private {shaka.Player.LoadMode} */
@@ -560,7 +562,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     this.video_ = null;
 
     /** @private {HTMLElement} */
-    this.videoContainer_ = null;
+    this.videoContainer_ = videoContainer;
 
     /**
      * Since we may not always have a text displayer created (e.g. before |load|

test/offline/storage_integration.js

@@ -743,7 +743,7 @@ filterDescribe('Storage', storageSupport, () => {
       // Use a real Player since Storage only uses the configuration and
       // networking engine.  This allows us to use Player.configure in these
       // tests.
-      player = new shaka.Player(null, ((player) => {
+      player = new shaka.Player(null, null, ((player) => {
         player.createNetworkingEngine = () => netEngine;
       }));
       await player.attach(videoElement);

test/player_unit.js

@@ -162,7 +162,7 @@ describe('Player', () => {
     }
 
     video = new shaka.test.FakeVideo(20);
-    player = new shaka.Player(null, dependencyInjector);
+    player = new shaka.Player(null, null, dependencyInjector);
     await player.attach(video);
     player.configure({
       // Ensures we don't get a warning about missing preference.