fix(tXml): html unescape node attributes with urls (#6267)

To provide feature parity with the `DOMParser.getAttribute` API which
would unescape html entities for free this PR unescapes url strings
which come from node attributes.

In a similar vain to
#6198 which unescapes
child strings.

docs/tutorials/upgrade.md

@@ -96,8 +96,10 @@ application:
   - Configuration changes:
     - `streaming.forceTransmuxTS` has been renamed to `streaming.forceTransmux`
       (deprecated in v4.3.0)
-    - `manifest.dash.manifestPreprocessor` callback now receives a type of `shaka.externs.xml.Node` instead of `Element`.
-    - `manifest.mss.manifestPreprocessor` callback now receives a type of `shaka.externs.xml.Node` instead of `Element`.
+    - Callbacks that used to accept `Element` now accept `shaka.externs.xml.Node`:
+      (`manifest.dash.manifestPreprocessor` and `manifest.mss.manifestPreprocessor`).
+      `getAttribute()` and `textContent` results must now be decoded if they might contain
+      escape sequences. You can use `shaka.util.StringUtils.htmlUnescape` for this purpose.
     - `streaming.useNativeHlsOnSafari` has removed. Now we have another config to do the same for FairPlay `streaming.useNativeHlsForFairPlay` or for HLS (any browser) `streaming.preferNativeHls`.
 
   - Plugin changes:

lib/dash/content_protection.js

@@ -191,6 +191,7 @@ shaka.dash.ContentProtection = class {
    * @return {string}
    */
   static getWidevineLicenseUrl(element) {
+    const StringUtils = shaka.util.StringUtils;
     const dashIfLaurlNode = shaka.util.TXml.findChildNS(
         element.node, shaka.dash.ContentProtection.DashIfNamespaceUri_,
         'Laurl',
@@ -204,7 +205,8 @@ shaka.dash.ContentProtection = class {
     const mslaurlNode = shaka.util.TXml.findChildNS(
         element.node, 'urn:microsoft', 'laurl');
     if (mslaurlNode) {
-      return mslaurlNode.attributes['licenseUrl'] || '';
+      return StringUtils.htmlUnescape(
+          mslaurlNode.attributes['licenseUrl']) || '';
     }
     return '';
   }
@@ -642,7 +644,8 @@ shaka.dash.ContentProtection = class {
     }
 
     const ivHex = cryptoPeriod.attributes['IV'];
-    const keyUri = cryptoPeriod.attributes['keyUriTemplate'];
+    const keyUri = shaka.util.StringUtils.htmlUnescape(
+        cryptoPeriod.attributes['keyUriTemplate']);
     if (!ivHex || !keyUri) {
       throw new shaka.util.Error(
           shaka.util.Error.Severity.CRITICAL,

lib/dash/segment_base.js

@@ -16,6 +16,7 @@ goog.require('shaka.media.WebmSegmentIndexParser');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.ObjectUtils');
+goog.require('shaka.util.StringUtils');
 goog.require('shaka.util.TXml');
 goog.requireType('shaka.dash.DashParser');
 goog.requireType('shaka.media.PresentationTimeline');
@@ -39,6 +40,7 @@ shaka.dash.SegmentBase = class {
     const MpdUtils = shaka.dash.MpdUtils;
     const TXml = shaka.util.TXml;
     const ManifestParserUtils = shaka.util.ManifestParserUtils;
+    const StringUtils = shaka.util.StringUtils;
 
     const initialization =
         MpdUtils.inheritChild(context, callback, 'Initialization');
@@ -49,7 +51,9 @@ shaka.dash.SegmentBase = class {
     let resolvedUris = context.representation.getBaseUris();
     const uri = initialization.attributes['sourceURL'];
     if (uri) {
-      resolvedUris = ManifestParserUtils.resolveUris(resolvedUris, [uri]);
+      resolvedUris = ManifestParserUtils.resolveUris(resolvedUris, [
+        StringUtils.htmlUnescape(uri),
+      ]);
     }
 
     let startByte = 0;
@@ -244,13 +248,15 @@ shaka.dash.SegmentBase = class {
     const ManifestParserUtils = shaka.util.ManifestParserUtils;
     const MpdUtils = shaka.dash.MpdUtils;
     const SegmentBase = shaka.dash.SegmentBase;
+    const StringUtils = shaka.util.StringUtils;
 
     const representationIndex = MpdUtils.inheritChild(
         context, SegmentBase.fromInheritance_, 'RepresentationIndex');
 
     let indexUris = context.representation.getBaseUris();
     if (representationIndex) {
-      const representationUri = representationIndex.attributes['sourceURL'];
+      const representationUri =
+        StringUtils.htmlUnescape(representationIndex.attributes['sourceURL']);
       if (representationUri) {
         indexUris = ManifestParserUtils.resolveUris(
             indexUris, [representationUri]);

lib/dash/segment_list.js

@@ -16,6 +16,7 @@ goog.require('shaka.media.SegmentReference');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.Functional');
 goog.require('shaka.util.ManifestParserUtils');
+goog.require('shaka.util.StringUtils');
 goog.require('shaka.util.TXml');
 goog.requireType('shaka.dash.DashParser');
 goog.requireType('shaka.media.PresentationTimeline');
@@ -290,6 +291,7 @@ shaka.dash.SegmentList = class {
     ].filter(Functional.isNotNull);
 
     const TXml = shaka.util.TXml;
+    const StringUtils = shaka.util.StringUtils;
     // Search each SegmentList for one with at least one SegmentURL element,
     // select the first one, and convert each SegmentURL element to a tuple.
     return segmentLists
@@ -305,7 +307,7 @@ shaka.dash.SegmentList = class {
                 'attribute or SegmentTimeline, which must be accurate.');
           }
 
-          const uri = urlNode.attributes['media'];
+          const uri = StringUtils.htmlUnescape(urlNode.attributes['media']);
           const range = TXml.parseAttr(
               urlNode, 'mediaRange', TXml.parseRange,
               {start: 0, end: null});

lib/dash/segment_template.js

@@ -17,6 +17,7 @@ goog.require('shaka.util.Error');
 goog.require('shaka.util.IReleasable');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.ObjectUtils');
+goog.require('shaka.util.StringUtils');
 goog.requireType('shaka.dash.DashParser');
 goog.requireType('shaka.media.PresentationTimeline');
 
@@ -195,6 +196,7 @@ shaka.dash.SegmentTemplate = class {
   static parseSegmentTemplateInfo_(context) {
     const SegmentTemplate = shaka.dash.SegmentTemplate;
     const MpdUtils = shaka.dash.MpdUtils;
+    const StringUtils = shaka.util.StringUtils;
     const segmentInfo =
         MpdUtils.parseSegmentInfo(context, SegmentTemplate.fromInheritance_);
 
@@ -211,7 +213,7 @@ shaka.dash.SegmentTemplate = class {
       unscaledPresentationTimeOffset:
           segmentInfo.unscaledPresentationTimeOffset,
       timeline: segmentInfo.timeline,
-      mediaTemplate: media,
+      mediaTemplate: media && StringUtils.htmlUnescape(media),
       indexTemplate: index,
     };
   }
@@ -534,11 +536,12 @@ shaka.dash.SegmentTemplate = class {
     const ManifestParserUtils = shaka.util.ManifestParserUtils;
     const SegmentTemplate = shaka.dash.SegmentTemplate;
 
-    const initialization = MpdUtils.inheritAttribute(
+    let initialization = MpdUtils.inheritAttribute(
         context, SegmentTemplate.fromInheritance_, 'initialization');
     if (!initialization) {
       return null;
     }
+    initialization = shaka.util.StringUtils.htmlUnescape(initialization);
 
     const repId = context.representation.id;
     const bandwidth = context.bandwidth || null;