fix: unnecessary parsing of in-band pssh when pssh is in the manifest (…

…#5198)

When pssh is provided in the manifest we do not need to parse in-band pssh even if the drm.parseInbandPssh setting is true.

Fixes #5197

Cherry-picked to v4.2.x

lib/media/drm_engine.js

@@ -133,6 +133,9 @@ shaka.media.DrmEngine = class {
 
     /** @private {Promise} */
     this.mediaKeysAttached_ = null;
+
+    /** @private {?shaka.extern.InitDataOverride} */
+    this.manifestInitData_ = null;
   }
 
   /** @override */
@@ -480,18 +483,18 @@ shaka.media.DrmEngine = class {
           () => this.closeOpenSessions_());
     }
 
-    const manifestInitData = this.currentDrmInfo_ ?
-      this.currentDrmInfo_.initData.find(
+    this.manifestInitData_ = this.currentDrmInfo_ ?
+      (this.currentDrmInfo_.initData.find(
           (initDataOverride) => initDataOverride.initData.length > 0,
-      ) : null;
+      ) || null) : null;
 
     /**
      * We can attach media keys before the playback actually begins when:
      *  - If we are not using FairPlay Modern EME
      *  - Some initData already has been generated (through the manifest)
      *  - In case of an offline session
      */
-    if (manifestInitData ||
+    if (this.manifestInitData_ ||
         this.currentDrmInfo_.keySystem !== 'com.apple.fps' ||
         this.offlineSessionIds_.length) {
       await this.attachMediaKeys_();
@@ -504,7 +507,7 @@ shaka.media.DrmEngine = class {
     // Also suppress 'encrypted' events when parsing in-band ppsh
     // from media segments because that serves the same purpose as the
     // 'encrypted' events.
-    if (!manifestInitData && !this.offlineSessionIds_.length &&
+    if (!this.manifestInitData_ && !this.offlineSessionIds_.length &&
         !this.config_.parseInbandPsshEnabled) {
       this.eventManager_.listen(
           this.video_, 'encrypted', (e) => this.onEncryptedEvent_(e));
@@ -2353,7 +2356,7 @@ shaka.media.DrmEngine = class {
    * @return {!Promise<void>}
    */
   parseInbandPssh(contentType, mediaSegment) {
-    if (!this.config_.parseInbandPsshEnabled) {
+    if (!this.config_.parseInbandPsshEnabled || this.manifestInitData_) {
       return Promise.resolve();
     }