fix: Unmask errors on LL (#5908)

lib/media/streaming_engine.js

@@ -1351,6 +1351,7 @@ shaka.media.StreamingEngine = class {
         let remaining = new Uint8Array(0);
         let processingResult = false;
         let callbackCalled = false;
+        let streamDataCallbackError;
         const streamDataCallback = async (data) => {
           if (processingResult) {
             // If the fallback result processing was triggered, don't also
@@ -1363,40 +1364,47 @@ shaka.media.StreamingEngine = class {
           if (this.fatalError_) {
             return;
           }
-          // Append the data with complete boxes.
-          // Every time streamDataCallback gets called, append the new data to
-          // the remaining data.
-          // Find the last fully completed Mdat box, and slice the data into two
-          // parts: the first part with completed Mdat boxes, and the second
-          // part with an incomplete box.
-          // Append the first part, and save the second part as remaining data,
-          // and handle it with the next streamDataCallback call.
-          remaining = this.concatArray_(remaining, data);
-          let sawMDAT = false;
-          let offset = 0;
-          new shaka.util.Mp4Parser()
-              .box('mdat', (box) => {
-                offset = box.size + box.start;
-                sawMDAT = true;
-              })
-              .parse(remaining, /* partialOkay= */ false,
+          try {
+            // Append the data with complete boxes.
+            // Every time streamDataCallback gets called, append the new data
+            // to the remaining data.
+            // Find the last fully completed Mdat box, and slice the data into
+            // two parts: the first part with completed Mdat boxes, and the
+            // second part with an incomplete box.
+            // Append the first part, and save the second part as remaining
+            // data, and handle it with the next streamDataCallback call.
+            remaining = this.concatArray_(remaining, data);
+            let sawMDAT = false;
+            let offset = 0;
+            new shaka.util.Mp4Parser()
+                .box('mdat', (box) => {
+                  offset = box.size + box.start;
+                  sawMDAT = true;
+                })
+                .parse(remaining, /* partialOkay= */ false,
+                    /* isChunkedData= */ true);
+            if (sawMDAT) {
+              const dataToAppend = remaining.subarray(0, offset);
+              remaining = remaining.subarray(offset);
+              await this.append_(
+                  mediaState, presentationTime, stream, reference, dataToAppend,
                   /* isChunkedData= */ true);
-          if (sawMDAT) {
-            const dataToAppend = remaining.subarray(0, offset);
-            remaining = remaining.subarray(offset);
-            await this.append_(
-                mediaState, presentationTime, stream, reference, dataToAppend,
-                /* isChunkedData= */ true);
-
-            if (mediaState.segmentPrefetch && mediaState.segmentIterator) {
-              mediaState.segmentPrefetch.prefetchSegments(
-                  reference, /* skipFirst= */ true);
+
+              if (mediaState.segmentPrefetch && mediaState.segmentIterator) {
+                mediaState.segmentPrefetch.prefetchSegments(
+                    reference, /* skipFirst= */ true);
+              }
             }
+          } catch (error) {
+            streamDataCallbackError = error;
           }
         };
 
         const result =
             await this.fetch_(mediaState, reference, streamDataCallback);
+        if (streamDataCallbackError) {
+          throw streamDataCallbackError;
+        }
         if (!callbackCalled) {
           // In some environments, we might be forced to use network plugins
           // that don't support streamDataCallback. In those cases, as a