[HLS] Do not try to seek inside buffer when no chunks are in the buffer

When a `HlsSampleStreamWrapper` has no tracks enabled after track selection, it will clear the `mediaChunks` as well as the the sample queue. However, when the tracks of it are newly re-enabled, we should not attempt to seek inside buffer while there is still no chunks at least partially in the buffer.

Issue: #2598

PiperOrigin-RevId: 783754042
(cherry picked from commit ded7742)

Author: tianyif

RELEASENOTES.md

@@ -20,6 +20,10 @@ This release includes the following changes since the
     *   Remove check for available commands when sending custom commands to a
         legacy `MediaBrowserServiceCompat`. This is in parity with the behavior
         of legacy controllers/browsers when connected to a legacy app.
+* HLS extension
+    *   Fix bug where `HlsSampleStreamWrapper` attempts to seek inside buffer
+        when there are no chunks available in the buffer
+        [#2598](https://github.com/androidx/media/issues/2598).
 
 ### 1.8.0-rc01 (2025-07-16)
 

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/HlsSampleStreamWrapper.java

@@ -516,7 +516,10 @@ public boolean seekToUs(long positionUs, boolean forceReset) {
     }
 
     // If we're not forced to reset, try and seek within the buffer.
-    if (sampleQueuesBuilt && !forceReset && seekInsideBufferUs(positionUs, seekToMediaChunk)) {
+    if (sampleQueuesBuilt
+        && !forceReset
+        && !mediaChunks.isEmpty()
+        && seekInsideBufferUs(positionUs, seekToMediaChunk)) {
       return false;
     }