Small cleanup.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=123739334

library/src/main/java/com/google/android/exoplayer/C.java

@@ -46,7 +46,7 @@ public interface C {
   /**
    * The number of nanoseconds in one second.
    */
-  public static final long NANOS_PER_SECOND = 1000000000L;
+  long NANOS_PER_SECOND = 1000000000L;
 
   /**
    * Represents an unbounded length of data.
@@ -203,6 +203,11 @@ public interface C {
   int DEFAULT_TEXT_BUFFER_SIZE = 2 * DEFAULT_BUFFER_SEGMENT_SIZE;
 
   /**
+   * A default size in bytes for a metadata buffer.
+   */
+  int DEFAULT_METADATA_BUFFER_SIZE = 2 * DEFAULT_BUFFER_SEGMENT_SIZE;
+
+  /**
    * A default size in bytes for a muxed buffer (e.g. containing video, audio and text).
    */
   int DEFAULT_MUXED_BUFFER_SIZE = DEFAULT_VIDEO_BUFFER_SIZE

library/src/main/java/com/google/android/exoplayer/TrackSelectionArray.java

@@ -33,8 +33,7 @@ public final class TrackSelectionArray {
   private int hashCode;
 
   /**
-   * @param trackSelections The selections. Must not be null or contain null elements, but may be
-   *     empty.
+   * @param trackSelections The selections. Must not be null, but may contain null elements.
    */
   public TrackSelectionArray(TrackSelection... trackSelections) {
     this.trackSelections = trackSelections;

library/src/main/java/com/google/android/exoplayer/util/Util.java

@@ -789,6 +789,8 @@ public final class Util {
         return C.DEFAULT_VIDEO_BUFFER_SIZE;
       case C.TRACK_TYPE_TEXT:
         return C.DEFAULT_TEXT_BUFFER_SIZE;
+      case C.TRACK_TYPE_METADATA:
+        return C.DEFAULT_METADATA_BUFFER_SIZE;
       default:
         throw new IllegalStateException();
     }