Advertise adaptive support in LibvpxVideoTrackRenderer.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=122247836

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/LibvpxVideoTrackRenderer.java

@@ -133,7 +133,7 @@ public final class LibvpxVideoTrackRenderer extends TrackRenderer {
   @Override
   @Override
   protected int supportsFormat(Format format) {
   protected int supportsFormat(Format format) {
     return isLibvpxAvailable() && MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
     return isLibvpxAvailable() && MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
-        ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
+        ? (FORMAT_HANDLED | ADAPTIVE_SEAMLESS) : FORMAT_UNSUPPORTED_TYPE;
   }
   }
 
 
   @Override
   @Override