fix(UI): Fix resolution selection on src= (shaka-project#5367)

With this change, when we are in src= mode we only leave the automatic
mode in the resolution selector, since we will not be able to change the
resolution.

Fixes shaka-project#5330

ui/resolution_selection.js

@@ -8,6 +8,7 @@
 goog.provide('shaka.ui.ResolutionSelection');
 
 goog.require('goog.asserts');
+goog.require('shaka.Player');
 goog.require('shaka.ui.Controls');
 goog.require('shaka.ui.Enums');
 goog.require('shaka.ui.Locales');
@@ -67,7 +68,12 @@ shaka.ui.ResolutionSelection = class extends shaka.ui.SettingsMenu {
   /** @private */
   updateResolutionSelection_() {
     /** @type {!Array.<shaka.extern.Track>} */
-    let tracks = this.player.getVariantTracks();
+    let tracks = [];
+    // When played with src=, the variant tracks available from
+    // player.getVariantTracks() represent languages, not resolutions.
+    if (this.player.getLoadMode() != shaka.Player.LoadMode.SRC_EQUALS) {
+      tracks = this.player.getVariantTracks();
+    }
 
     // If there is a selected variant track, then we filter out any tracks in
     // a different language.  Then we use those remaining tracks to display the