V2 Extension fixes

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120699171

extensions/flac/src/main/java/com/google/android/exoplayer/ext/flac/LibflacAudioTrackRenderer.java

@@ -52,7 +52,7 @@ public class LibflacAudioTrackRenderer extends AudioDecoderTrackRenderer {
   }
   @Override
   protected int supportsFormat(Format format) {
-    return MimeTypes.AUDIO_FLAC.equalsIgnoreCase(format.sampleMimeType)
+    return isLibflacAvailable() && MimeTypes.AUDIO_FLAC.equalsIgnoreCase(format.sampleMimeType)
         ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
   }
 

extensions/opus/src/main/java/com/google/android/exoplayer/ext/opus/LibopusAudioTrackRenderer.java

@@ -60,7 +60,7 @@ public final class LibopusAudioTrackRenderer extends AudioDecoderTrackRenderer {
 
   @Override
   protected int supportsFormat(Format format) {
-    return MimeTypes.AUDIO_OPUS.equalsIgnoreCase(format.sampleMimeType)
+    return isLibopusAvailable() && MimeTypes.AUDIO_OPUS.equalsIgnoreCase(format.sampleMimeType)
         ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
   }
 

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

@@ -186,7 +186,7 @@ public final class LibvpxVideoTrackRenderer extends TrackRenderer {
 
   @Override
   protected int supportsFormat(Format format) {
-    return MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
+    return isLibvpxAvailable() && MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
         ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
   }
 

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

@@ -83,7 +83,6 @@ public final class VpxOutputBuffer extends OutputBuffer {
       yuvPlanes = new ByteBuffer[3];
     }
     // Rewrapping has to be done on every frame since the stride might have changed.
-    data.position(0);
     yuvPlanes[0] = data.slice();
     yuvPlanes[0].limit(yLength);
     data.position(yLength);
@@ -103,9 +102,10 @@ public final class VpxOutputBuffer extends OutputBuffer {
   private void initData(int size) {
     if (data == null || data.capacity() < size) {
       data = ByteBuffer.allocateDirect(size);
+    } else {
+      data.position(0);
+      data.limit(size);
     }
-    data.position(0);
-    data.limit(size);
   }
 
 }

library/src/main/java/com/google/android/exoplayer/extractor/ExtractorSampleSource.java

@@ -59,6 +59,7 @@ import java.util.List;
  * <li>MPEG PS ({@link com.google.android.exoplayer.extractor.ts.PsExtractor})</li>
  * <li>FLV ({@link com.google.android.exoplayer.extractor.flv.FlvExtractor})</li>
  * <li>WAV ({@link com.google.android.exoplayer.extractor.wav.WavExtractor})</li>
+ * <li>FLAC (only available if the FLAC extension is built and included)</li>
  * </ul>
  *
  * <p>Seeking in AAC, MPEG TS and FLV streams is not supported.
@@ -188,6 +189,13 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
     } catch (ClassNotFoundException e) {
       // Extractor not found.
     }
+    try {
+      DEFAULT_EXTRACTOR_CLASSES.add(
+          Class.forName("com.google.android.exoplayer.ext.flac.FlacExtractor")
+              .asSubclass(Extractor.class));
+    } catch (ClassNotFoundException e) {
+      // Extractor not found.
+    }
   }
 
   private final Loader loader;