feat: Improve performance of setStreamProperties on low-end devices (s…

…haka-project#5380)

By reducing the number of promises in the Promises.all array we gain
performance on low-end devices.

lib/media/media_source_engine.js

@@ -989,10 +989,12 @@ shaka.media.MediaSourceEngine = class {
       this.textEngine_.setAppendWindow(appendWindowStart, appendWindowEnd);
       return;
     }
+    const operations = [];
+
     const hasChangedCodecs =
         await this.codecSwitchIfNecessary_(contentType, stream, streamsByType);
 
-    await Promise.all([
+    if (!hasChangedCodecs) {
       // Queue an abort() to help MSE splice together overlapping segments.
       // We set appendWindowEnd when we change periods in DASH content, and the
       // period transition may result in overlap.
@@ -1001,17 +1003,21 @@ shaka.media.MediaSourceEngine = class {
       // always enter a PARSING_MEDIA_SEGMENT state and we can't change the
       // timestamp offset.  By calling abort(), we reset the state so we can
       // set it.
-      hasChangedCodecs ? Promise.resolve() : this.enqueueOperation_(
-          contentType,
-          () => this.abort_(contentType)),
-      ignoreTimestampOffset ? Promise.resolve() : this.enqueueOperation_(
+      operations.push(this.enqueueOperation_(
           contentType,
-          () => this.setTimestampOffset_(contentType, timestampOffset)),
-      this.enqueueOperation_(
+          () => this.abort_(contentType)));
+    }
+    if (!ignoreTimestampOffset) {
+      operations.push(this.enqueueOperation_(
           contentType,
-          () => this.setAppendWindow_(
-              contentType, appendWindowStart, appendWindowEnd)),
-    ]);
+          () => this.setTimestampOffset_(contentType, timestampOffset)));
+    }
+    operations.push(this.enqueueOperation_(
+        contentType,
+        () => this.setAppendWindow_(
+            contentType, appendWindowStart, appendWindowEnd)));
+
+    await Promise.all(operations);
   }
 
   /**