fix: Install polyfills for Comcast X1 devices

externs/comcast.js

@@ -0,0 +1,19 @@
+/*! @license
+ * Shaka Player
+ * Copyright 2016 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Externs for Comcast
+ *
+ * @externs
+ */
+
+
+/** @const */
+var ServiceManager = {};
+
+
+/** @type {string} */
+ServiceManager.getServiceForJavaScript;

lib/polyfill/media_capabilities.js

@@ -61,7 +61,8 @@ shaka.polyfill.MediaCapabilities = class {
         shaka.util.Platform.isWebOS() ||
         shaka.util.Platform.isTizen() ||
         shaka.util.Platform.isEOS() ||
-        shaka.util.Platform.isHisense()) {
+        shaka.util.Platform.isHisense() ||
+        shaka.util.Platform.isComcastX1()) {
       canUseNativeMCap = false;
     }
     if (canUseNativeMCap && navigator.mediaCapabilities) {

lib/polyfill/mediasource.js

@@ -87,6 +87,18 @@ shaka.polyfill.MediaSource = class {
       // the player from trying to play opus on Tizen, we will override media
       // source to always reject opus content.
       shaka.polyfill.MediaSource.rejectCodec_('opus');
+    } else if (shaka.util.Platform.isComcastX1()) {
+      // XOne look to be like safari 8 which do not correctly
+      // implement abort() on SourceBuffer.
+      // Calling abort() before appending a segment causes that segment to be
+      // incomplete in the buffer.
+      // Bug filed: https://bugs.webkit.org/show_bug.cgi?id=165342
+      shaka.polyfill.MediaSource.stubAbort_();
+      // If you remove up to a keyframe, Webkit 601.x.x incorrectly will also
+      // remove that keyframe and the content up to the next.
+      // Offsetting the end of the removal range seems to help.
+      // Bug filed: https://bugs.webkit.org/show_bug.cgi?id=177884
+      shaka.polyfill.MediaSource.patchRemovalRange_();
     } else {
       shaka.log.info('Using native MSE as-is.');
     }

lib/util/platform.js

@@ -300,9 +300,9 @@ shaka.util.Platform = class {
         !shaka.util.Platform.isOrange() &&
         !shaka.util.Platform.isPS4() &&
         !shaka.util.Platform.isAmazonFireTV() &&
-        !shaka.util.Platform.isWPE() &&
         !shaka.util.Platform.isZenterio() &&
-        !shaka.util.Platform.isSkyQ();
+        !shaka.util.Platform.isSkyQ() &&
+        !shaka.util.Platform.isComcastX1();
   }
 
   /**
@@ -354,6 +354,19 @@ shaka.util.Platform = class {
     return shaka.util.Platform.userAgentContains_('Sky_STB');
   }
 
+  /**
+   * Check if the current platform is Comcast X1.
+   */
+  static isComcastX1() {
+    const rdk = window.ServiceManager &&
+        window.ServiceManager.getServiceForJavaScript;
+    return rdk && shaka.util.Platform.userAgentContains_('WPE') &&
+        navigator.platform &&
+        navigator.platform.includes('Linux aarch64') &&
+        shaka.util.Platform.userAgentContains_('AppleWebKit') &&
+        shaka.util.Platform.userAgentContains_('Version/8.0');
+  }
+
   /**
    * Check if the current platform is Amazon Fire TV.
    * https://developer.amazon.com/docs/fire-tv/identify-amazon-fire-tv-devices.html
@@ -364,14 +377,6 @@ shaka.util.Platform = class {
     return shaka.util.Platform.userAgentContains_('AFT');
   }
 
-  /**
-   * Check if the current platform is Comcast X1.
-   * @return {boolean}
-   */
-  static isWPE() {
-    return shaka.util.Platform.userAgentContains_('WPE');
-  }
-
   /**
    * Check if the current platform is Deutsche Telecom Zenterio STB.
    * @return {boolean}
@@ -536,7 +541,7 @@ shaka.util.Platform = class {
         Platform.isPS5() || Platform.isAmazonFireTV() ||
         Platform.isEOS() || Platform.isAPL() ||
         Platform.isVirginMedia() || Platform.isOrange() ||
-        Platform.isWPE() || Platform.isChromecast() ||
+        Platform.isComcastX1() || Platform.isChromecast() ||
         Platform.isHisense() || Platform.isZenterio()) {
       return true;
     }