Prevent negative total buffered duration at the point where it is calculated.

In some edge cases the renderer position may be slightly ahead of the
buffered position and the total buffered duration is thus negative. We already
filter that in ExoPlayerImpl for the publicly accessible value. However, we
forward the unfiltered value to other components like the LoadControl, which
may be confusing.

Issue:#6015
PiperOrigin-RevId: 253780460

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -512,7 +512,7 @@ import java.util.concurrent.CopyOnWriteArrayList;
 
   @Override
   public long getTotalBufferedDuration() {
-    return Math.max(0, C.usToMs(playbackInfo.totalBufferedDurationUs));
+    return C.usToMs(playbackInfo.totalBufferedDurationUs);
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImplInternal.java

@@ -1797,9 +1797,12 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
   private long getTotalBufferedDurationUs(long bufferedPositionInLoadingPeriodUs) {
     MediaPeriodHolder loadingPeriodHolder = queue.getLoadingPeriod();
-    return loadingPeriodHolder == null
-        ? 0
-        : bufferedPositionInLoadingPeriodUs - loadingPeriodHolder.toPeriodTime(rendererPositionUs);
+    if (loadingPeriodHolder == null) {
+      return 0;
+    }
+    long totalBufferedDurationUs =
+        bufferedPositionInLoadingPeriodUs - loadingPeriodHolder.toPeriodTime(rendererPositionUs);
+    return Math.max(0, totalBufferedDurationUs);
   }
 
   private void updateLoadControlTrackSelection(