Move DashMediaSource and SsMediaSource to new SampleQueue methods

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=160130540

library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java

@@ -36,7 +36,7 @@ import java.util.List;
  * May also be configured to expose additional embedded {@link SampleStream}s.
  */
 public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, SequenceableLoader,
-    Loader.Callback<Chunk> {
+    Loader.Callback<Chunk>, Loader.ReleaseCallback {
 
   private final int primaryTrackType;
   private final int[] embeddedTrackTypes;
@@ -106,17 +106,20 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     lastSeekPositionUs = positionUs;
   }
 
+  // TODO: Generalize this method to also discard from the primary sample queue and stop discarding
+  // from this queue in readData and skipData. This will cause samples to be kept in the queue until
+  // they've been rendered, rather than being discarded as soon as they're read by the renderer.
+  // This will make in-buffer seeks more likely when seeking slightly forward from the current
+  // position. This change will need handling with care, in particular when considering removal of
+  // chunks from the front of the mediaChunks list.
   /**
-   * Discards buffered media for embedded tracks that are not currently selected, up to the
-   * specified position.
+   * Discards buffered media for embedded tracks, up to the specified position.
    *
    * @param positionUs The position to discard up to, in microseconds.
    */
-  public void discardUnselectedEmbeddedTracksTo(long positionUs) {
+  public void discardEmbeddedTracksTo(long positionUs) {
     for (int i = 0; i < embeddedSampleQueues.length; i++) {
-      if (!embeddedTracksSelected[i]) {
-        embeddedSampleQueues[i].skipToKeyframeBefore(positionUs, true);
-      }
+      embeddedSampleQueues[i].discardTo(positionUs, true, embeddedTracksSelected[i]);
     }
   }
 
@@ -135,7 +138,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
       if (embeddedTrackTypes[i] == trackType) {
         Assertions.checkState(!embeddedTracksSelected[i]);
         embeddedTracksSelected[i] = true;
-        embeddedSampleQueues[i].skipToKeyframeBefore(positionUs, true);
+        embeddedSampleQueues[i].rewind();
+        embeddedSampleQueues[i].advanceTo(positionUs, true, true);
         return new EmbeddedSampleStream(this, embeddedSampleQueues[i], i);
       }
     }
@@ -181,19 +185,15 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   public void seekToUs(long positionUs) {
     lastSeekPositionUs = positionUs;
     // If we're not pending a reset, see if we can seek within the primary sample queue.
-    boolean seekInsideBuffer = !isPendingReset() && primarySampleQueue.skipToKeyframeBefore(
-        positionUs, positionUs < getNextLoadPositionUs());
+    boolean seekInsideBuffer = !isPendingReset() && primarySampleQueue.advanceTo(positionUs, true,
+        positionUs < getNextLoadPositionUs());
     if (seekInsideBuffer) {
-      // We succeeded. We need to discard any chunks that we've moved past and perform the seek for
-      // any embedded streams as well.
-      while (mediaChunks.size() > 1
-          && mediaChunks.get(1).getFirstSampleIndex(0) <= primarySampleQueue.getReadIndex()) {
-        mediaChunks.removeFirst();
-      }
-      // TODO: For this to work correctly, the embedded streams must not discard anything from their
-      // sample queues beyond the current read position of the primary stream.
+      // We succeeded. Discard samples and corresponding chunks prior to the seek position.
+      discardDownstreamMediaChunks(primarySampleQueue.getReadIndex());
+      primarySampleQueue.discardToRead();
       for (SampleQueue embeddedSampleQueue : embeddedSampleQueues) {
-        embeddedSampleQueue.skipToKeyframeBefore(positionUs, true);
+        embeddedSampleQueue.rewind();
+        embeddedSampleQueue.discardTo(positionUs, true, false);
       }
     } else {
       // We failed, and need to restart.
@@ -217,11 +217,22 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
    * This method should be called when the stream is no longer required.
    */
   public void release() {
-    primarySampleQueue.disable();
+    boolean releasedSynchronously = loader.release(this);
+    if (!releasedSynchronously) {
+      // Discard as much as we can synchronously.
+      primarySampleQueue.discardToEnd();
+      for (SampleQueue embeddedSampleQueue : embeddedSampleQueues) {
+        embeddedSampleQueue.discardToEnd();
+      }
+    }
+  }
+
+  @Override
+  public void onLoaderReleased() {
+    primarySampleQueue.reset(true);
     for (SampleQueue embeddedSampleQueue : embeddedSampleQueues) {
-      embeddedSampleQueue.disable();
+      embeddedSampleQueue.reset(true);
     }
-    loader.release();
   }
 
   // SampleStream implementation.
@@ -246,17 +257,22 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
       return C.RESULT_NOTHING_READ;
     }
     discardDownstreamMediaChunks(primarySampleQueue.getReadIndex());
-    return primarySampleQueue.readData(formatHolder, buffer, formatRequired, loadingFinished,
+    int result = primarySampleQueue.read(formatHolder, buffer, formatRequired, loadingFinished,
         lastSeekPositionUs);
+    if (result == C.RESULT_BUFFER_READ) {
+      primarySampleQueue.discardToRead();
+    }
+    return result;
   }
 
   @Override
   public void skipData(long positionUs) {
     if (loadingFinished && positionUs > primarySampleQueue.getLargestQueuedTimestampUs()) {
-      primarySampleQueue.skipAll();
+      primarySampleQueue.advanceToEnd();
     } else {
-      primarySampleQueue.skipToKeyframeBefore(positionUs, true);
+      primarySampleQueue.advanceTo(positionUs, true, true);
     }
+    primarySampleQueue.discardToRead();
   }
 
   // Loader.Callback implementation.
@@ -416,18 +432,18 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     if (mediaChunks.size() <= queueLength) {
       return false;
     }
-    long startTimeUs = 0;
+    BaseMediaChunk removed;
+    long startTimeUs;
     long endTimeUs = mediaChunks.getLast().endTimeUs;
-    BaseMediaChunk removed = null;
-    while (mediaChunks.size() > queueLength) {
+    do {
       removed = mediaChunks.removeLast();
       startTimeUs = removed.startTimeUs;
-      loadingFinished = false;
-    }
+    } while (mediaChunks.size() > queueLength);
     primarySampleQueue.discardUpstreamSamples(removed.getFirstSampleIndex(0));
     for (int i = 0; i < embeddedSampleQueues.length; i++) {
       embeddedSampleQueues[i].discardUpstreamSamples(removed.getFirstSampleIndex(i + 1));
     }
+    loadingFinished = false;
     eventDispatcher.upstreamDiscarded(primaryTrackType, startTimeUs, endTimeUs);
     return true;
   }
@@ -442,8 +458,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     private final SampleQueue sampleQueue;
     private final int index;
 
-    public EmbeddedSampleStream(ChunkSampleStream<T> parent, SampleQueue sampleQueue,
-        int index) {
+    public EmbeddedSampleStream(ChunkSampleStream<T> parent, SampleQueue sampleQueue, int index) {
       this.parent = parent;
       this.sampleQueue = sampleQueue;
       this.index = index;
@@ -457,9 +472,9 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     @Override
     public void skipData(long positionUs) {
       if (loadingFinished && positionUs > sampleQueue.getLargestQueuedTimestampUs()) {
-        sampleQueue.skipAll();
+        sampleQueue.advanceToEnd();
       } else {
-        sampleQueue.skipToKeyframeBefore(positionUs, true);
+        sampleQueue.advanceTo(positionUs, true, true);
       }
     }
 
@@ -474,7 +489,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
       if (isPendingReset()) {
         return C.RESULT_NOTHING_READ;
       }
-      return sampleQueue.readData(formatHolder, buffer, formatRequired, loadingFinished,
+      return sampleQueue.read(formatHolder, buffer, formatRequired, loadingFinished,
           lastSeekPositionUs);
     }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaPeriod.java

@@ -188,7 +188,7 @@ import java.util.List;
   @Override
   public void discardBuffer(long positionUs) {
     for (ChunkSampleStream<DashChunkSource> sampleStream : sampleStreams) {
-      sampleStream.discardUnselectedEmbeddedTracksTo(positionUs);
+      sampleStream.discardEmbeddedTracksTo(positionUs);
     }
   }