Remove unused parameter from ChunkSource.continueBuffering.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120691990

library/src/main/java/com/google/android/exoplayer/chunk/ChunkSampleSource.java

@@ -207,7 +207,7 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
   @Override
   public void continueBuffering(long positionUs) {
     downstreamPositionUs = positionUs;
-    chunkSource.continueBuffering(positionUs);
+    chunkSource.continueBuffering();
     if (!loader.isLoading()) {
       maybeStartLoading();
     }

library/src/main/java/com/google/android/exoplayer/chunk/ChunkSource.java

@@ -84,10 +84,8 @@ public interface ChunkSource {
    * Indicates to the source that it should still be checking for updates to the stream.
    * <p>
    * This method should only be called when the source is enabled.
-   *
-   * @param playbackPositionUs The current playback position.
    */
-  void continueBuffering(long playbackPositionUs);
+  void continueBuffering();
 
   /**
    * Evaluates whether {@link MediaChunk}s should be removed from the back of the queue.

library/src/main/java/com/google/android/exoplayer/dash/DashChunkSource.java

@@ -159,7 +159,7 @@ public class DashChunkSource implements ChunkSource {
   }
 
   @Override
-  public void continueBuffering(long playbackPositionUs) {
+  public void continueBuffering() {
     if (!currentManifest.dynamic || fatalError != null) {
       return;
     }

library/src/main/java/com/google/android/exoplayer/smoothstreaming/SmoothStreamingChunkSource.java

@@ -163,7 +163,7 @@ public class SmoothStreamingChunkSource implements ChunkSource {
   }
 
   @Override
-  public void continueBuffering(long playbackPositionUs) {
+  public void continueBuffering() {
     if (!currentManifest.isLive || fatalError != null) {
       return;
     }