Pull assertion and layer of indirection out from ChunkExtractorWrapper

It should be possible to remove ChunkExtractorWrapper from the track
output side as well (currently all extractor output is funneled via
ChunkExtractorWrapper just so it can adjust the format, which is kind
of unnecessary).

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=145083620

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

@@ -47,7 +47,8 @@ public final class ChunkExtractorWrapper implements ExtractorOutput, TrackOutput
 
   }
 
-  private final Extractor extractor;
+  public final Extractor extractor;
+
   private final Format manifestFormat;
   private final boolean preferManifestDrmInitData;
   private final boolean resendFormatOnInit;
@@ -99,20 +100,6 @@ public final class ChunkExtractorWrapper implements ExtractorOutput, TrackOutput
     }
   }
 
-  /**
-   * Reads from the provided {@link ExtractorInput}.
-   *
-   * @param input The {@link ExtractorInput} from which to read.
-   * @return One of {@link Extractor#RESULT_CONTINUE} and {@link Extractor#RESULT_END_OF_INPUT}.
-   * @throws IOException If an error occurred reading from the source.
-   * @throws InterruptedException If the thread was interrupted.
-   */
-  public int read(ExtractorInput input) throws IOException, InterruptedException {
-    int result = extractor.read(input, null);
-    Assertions.checkState(result != Extractor.RESULT_SEEK);
-    return result;
-  }
-
   // ExtractorOutput implementation.
 
   @Override

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

@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.extractor.SeekMap;
 import com.google.android.exoplayer2.source.chunk.ChunkExtractorWrapper.SeekMapOutput;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
 
@@ -120,10 +121,12 @@ public class ContainerMediaChunk extends BaseMediaChunk implements SeekMapOutput
       }
       // Load and decode the sample data.
       try {
+        Extractor extractor = extractorWrapper.extractor;
         int result = Extractor.RESULT_CONTINUE;
         while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
-          result = extractorWrapper.read(input);
+          result = extractor.read(input, null);
         }
+        Assertions.checkState(result != Extractor.RESULT_SEEK);
       } finally {
         bytesLoaded = (int) (input.getPosition() - dataSpec.absoluteStreamPosition);
       }

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

@@ -25,6 +25,7 @@ import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.source.chunk.ChunkExtractorWrapper.SeekMapOutput;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
@@ -142,10 +143,12 @@ public final class InitializationChunk extends Chunk implements SeekMapOutput,
       }
       // Load and decode the initialization data.
       try {
+        Extractor extractor = extractorWrapper.extractor;
         int result = Extractor.RESULT_CONTINUE;
         while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
-          result = extractorWrapper.read(input);
+          result = extractor.read(input, null);
         }
+        Assertions.checkState(result != Extractor.RESULT_SEEK);
       } finally {
         bytesLoaded = (int) (input.getPosition() - dataSpec.absoluteStreamPosition);
       }