fix: Add new crossBoundaryStrategy for Apple browsers (#8345)

Related to #8335

Author: avelad

demo/config.js

@@ -598,6 +598,7 @@ shakaDemo.Config = class {
       'KEEP': 'Keep',
       'RESET': 'Reset',
       'RESET_TO_ENCRYPTED': 'Reset to encrypted',
+      'RESET_ON_ENCRYPTION_CHANGE': 'Reset on encryption change',
     };
 
     this.addBoolInput_('Start At Segment Boundary',

lib/config/cross_boundary_strategy.js

@@ -24,4 +24,10 @@ shaka.config.CrossBoundaryStrategy = {
    * boundary to an encrypted boundary.
    */
   'RESET_TO_ENCRYPTED': 'reset_to_encrypted',
+  /**
+   * Reset MediaSource, when transitioning from a plain
+   * boundary to an encrypted boundary or from an encrypted
+   * boundary to a plain boundary.
+   */
+  'RESET_ON_ENCRYPTION_CHANGE': 'RESET_ON_ENCRYPTION_CHANGE',
 };

lib/media/streaming_engine.js

@@ -3117,6 +3117,14 @@ shaka.media.StreamingEngine = class {
         this.config_.crossBoundaryStrategy = CrossBoundaryStrategy.KEEP;
       }
     }
+    if (this.config_.crossBoundaryStrategy ===
+          CrossBoundaryStrategy.RESET_ON_ENCRYPTION_CHANGE) {
+      if (lastInitRef.encrypted == initRef.encrypted) {
+        // We're crossing a plain to plain boundary or we're crossing a
+        // encrypted to encrypted boundary, allow the reference.
+        discard = false;
+      }
+    }
     // If discarded & seeked across a boundary, reset MediaSource.
     if (discard && mediaState.seeked) {
       shaka.log.debug(logPrefix, 'reset mediaSource',

lib/util/player_configuration.js

@@ -311,6 +311,11 @@ shaka.util.PlayerConfiguration = class {
           shaka.config.CrossBoundaryStrategy.RESET_TO_ENCRYPTED;
     }
 
+    if (shaka.util.Platform.isApple()) {
+      streaming.crossBoundaryStrategy =
+          shaka.config.CrossBoundaryStrategy.RESET_ON_ENCRYPTION_CHANGE;
+    }
+
     const networking = {
       forceHTTP: false,
       forceHTTPS: false,