Fix stalls on WebOS (#1820)

Disable the StallDetector on WebOS, where we often mistake slowness for stalling.

Fix for #1704

AUTHORS

@@ -15,6 +15,7 @@
 
 AdsWizz <*@adswizz.com>
 Alugha GmbH <*@alugha.com>
+Alvaro Velad Galvan <alvaro.velad@mirada.tv>
 Bonnier Broadcasting <*@bonnierbroadcasting.com>
 Bryan Huh <bhh1988@gmail.com>
 Esteban Dosztal <edosztal@gmail.com>

CONTRIBUTORS

@@ -23,6 +23,7 @@
 # Please keep the list sorted.
 
 Aaron Vaage <vaage@google.com>
+Alvaro Velad Galvan <alvaro.velad@mirada.tv>
 Andy Hochhaus <ahochhaus@samegoal.com>
 Benjamin Wallberg <benjamin.wallberg@bonnierbroadcasting.com>
 Bryan Huh <bhh1988@gmail.com>

lib/media/stall_detector.js

@@ -18,6 +18,7 @@
 goog.provide('shaka.media.StallDetector');
 goog.provide('shaka.media.StallDetector.Implementation');
 goog.provide('shaka.media.StallDetector.MediaElementImplementation');
+goog.require('shaka.util.Platform');
 
 /**
  * Some platforms/browsers can get stuck in the middle of a buffered range (e.g.
@@ -141,6 +142,11 @@ shaka.media.StallDetector.MediaElementImplementation = class {
 
   /** @override */
   shouldBeMakingProgress() {
+    // If we are in WebOS platform disable StallDetector. This is because WebOS
+    // TVs tend to have long hardware pipelines that respond slowly, so we tend
+    // to mistake slow operation for a stall.
+    if (shaka.util.Platform.isWebOS()) { return false; }
+
     // If we are not trying to play, the lack of change could be misidentified
     // as a stall.
     if (this.mediaElement_.paused) { return false; }

lib/util/platform.js

@@ -60,6 +60,15 @@ shaka.util.Platform = class {
     return shaka.util.Platform.userAgentContains_('Tizen 3');
   }
 
+  /**
+   * Check if the current platform is a WebOS.
+   *
+   * @return {boolean}
+   */
+  static isWebOS() {
+    return shaka.util.Platform.userAgentContains_('Web0S');
+  }
+
   /**
    * Check if the current platform is a Google Chromecast.
    *