Add static Util.EMPTY_BYTE_ARRAY

This prevents repeated instantiation of empty arrays.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=211941723

extensions/okhttp/src/main/java/com/google/android/exoplayer2/ext/okhttp/OkHttpDataSource.java

@@ -27,6 +27,7 @@ import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Predicate;
+import com.google.android.exoplayer2.util.Util;
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -301,7 +302,7 @@ public class OkHttpDataSource extends BaseDataSource implements HttpDataSource {
       requestBody = RequestBody.create(null, dataSpec.httpBody);
     } else if (dataSpec.httpMethod == DataSpec.HTTP_METHOD_POST) {
       // OkHttp requires a non-null body for POST requests.
-      requestBody = RequestBody.create(null, new byte[0]);
+      requestBody = RequestBody.create(null, Util.EMPTY_BYTE_ARRAY);
     }
     builder.method(dataSpec.getHttpMethodString(), requestBody);
     return builder.build();

library/core/src/main/java/com/google/android/exoplayer2/audio/SilenceSkippingAudioProcessor.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.audio;
 import android.support.annotation.IntDef;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.util.Util;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.nio.ByteBuffer;
@@ -102,8 +103,8 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
     outputBuffer = EMPTY_BUFFER;
     channelCount = Format.NO_VALUE;
     sampleRateHz = Format.NO_VALUE;
-    maybeSilenceBuffer = new byte[0];
-    paddingBuffer = new byte[0];
+    maybeSilenceBuffer = Util.EMPTY_BYTE_ARRAY;
+    paddingBuffer = Util.EMPTY_BYTE_ARRAY;
   }
 
   /**
@@ -234,8 +235,8 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
     channelCount = Format.NO_VALUE;
     sampleRateHz = Format.NO_VALUE;
     paddingSize = 0;
-    maybeSilenceBuffer = new byte[0];
-    paddingBuffer = new byte[0];
+    maybeSilenceBuffer = Util.EMPTY_BYTE_ARRAY;
+    paddingBuffer = Util.EMPTY_BYTE_ARRAY;
   }
 
   // Internal methods.

library/core/src/main/java/com/google/android/exoplayer2/audio/TrimmingAudioProcessor.java

@@ -44,7 +44,7 @@ import java.nio.ByteOrder;
     outputBuffer = EMPTY_BUFFER;
     channelCount = Format.NO_VALUE;
     sampleRateHz = Format.NO_VALUE;
-    endBuffer = new byte[0];
+    endBuffer = Util.EMPTY_BYTE_ARRAY;
   }
 
   /**
@@ -180,7 +180,7 @@ import java.nio.ByteOrder;
     buffer = EMPTY_BUFFER;
     channelCount = Format.NO_VALUE;
     sampleRateHz = Format.NO_VALUE;
-    endBuffer = new byte[0];
+    endBuffer = Util.EMPTY_BYTE_ARRAY;
   }
 
 }

library/core/src/main/java/com/google/android/exoplayer2/drm/HttpMediaDrmCallback.java

@@ -110,7 +110,7 @@ public final class HttpMediaDrmCallback implements MediaDrmCallback {
   public byte[] executeProvisionRequest(UUID uuid, ProvisionRequest request) throws IOException {
     String url =
         request.getDefaultUrl() + "&signedRequest=" + Util.fromUtf8Bytes(request.getData());
-    return executePost(dataSourceFactory, url, new byte[0], null);
+    return executePost(dataSourceFactory, url, Util.EMPTY_BYTE_ARRAY, null);
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/TsExtractor.java

@@ -544,7 +544,7 @@ public final class TsExtractor implements Extractor {
       if (mode == MODE_HLS && id3Reader == null) {
         // Setup an ID3 track regardless of whether there's a corresponding entry, in case one
         // appears intermittently during playback. See [Internal: b/20261500].
-        EsInfo dummyEsInfo = new EsInfo(TS_STREAM_TYPE_ID3, null, null, new byte[0]);
+        EsInfo dummyEsInfo = new EsInfo(TS_STREAM_TYPE_ID3, null, null, Util.EMPTY_BYTE_ARRAY);
         id3Reader = payloadReaderFactory.createPayloadReader(TS_STREAM_TYPE_ID3, dummyEsInfo);
         id3Reader.init(timestampAdjuster, output,
             new TrackIdGenerator(programNumber, TS_STREAM_TYPE_ID3, MAX_PID_PLUS_ONE));

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/Id3Decoder.java

@@ -759,7 +759,7 @@ public final class Id3Decoder implements MetadataDecoder {
   private static byte[] copyOfRangeIfValid(byte[] data, int from, int to) {
     if (to <= from) {
       // Invalid or zero length range.
-      return new byte[0];
+      return Util.EMPTY_BYTE_ARRAY;
     }
     return Arrays.copyOfRange(data, from, to);
   }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadAction.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.offline;
 import android.net.Uri;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
@@ -157,7 +158,7 @@ public abstract class DownloadAction {
     this.version = version;
     this.uri = uri;
     this.isRemoveAction = isRemoveAction;
-    this.data = data != null ? data : new byte[0];
+    this.data = data != null ? data : Util.EMPTY_BYTE_ARRAY;
   }
 
   /** Serializes itself into a byte array. */

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -111,6 +111,9 @@ public final class Util {
   public static final String DEVICE_DEBUG_INFO = DEVICE + ", " + MODEL + ", " + MANUFACTURER + ", "
       + SDK_INT;
 
+  /** An empty byte array. */
+  public static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
+
   private static final String TAG = "Util";
   private static final Pattern XS_DATE_TIME_PATTERN = Pattern.compile(
       "(\\d\\d\\d\\d)\\-(\\d\\d)\\-(\\d\\d)[Tt]"

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeExtractorInput.java

@@ -20,6 +20,7 @@ import static com.google.common.truth.Truth.assertThat;
 import android.util.SparseBooleanArray;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.extractor.ExtractorInput;
+import com.google.android.exoplayer2.util.Util;
 import java.io.EOFException;
 import java.io.IOException;
 
@@ -255,7 +256,7 @@ public final class FakeExtractorInput implements ExtractorInput {
     private boolean simulateIOErrors;
 
     public Builder() {
-      data = new byte[0];
+      data = Util.EMPTY_BYTE_ARRAY;
     }
 
     public Builder setData(byte[] data) {

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeTrackOutput.java

@@ -22,6 +22,7 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorInput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.Util;
 import java.io.EOFException;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -44,7 +45,7 @@ public final class FakeTrackOutput implements TrackOutput, Dumper.Dumpable {
   public Format format;
 
   public FakeTrackOutput() {
-    sampleData = new byte[0];
+    sampleData = Util.EMPTY_BYTE_ARRAY;
     sampleTimesUs = new ArrayList<>();
     sampleFlags = new ArrayList<>();
     sampleStartOffsets = new ArrayList<>();
@@ -53,7 +54,7 @@ public final class FakeTrackOutput implements TrackOutput, Dumper.Dumpable {
   }
 
   public void clear() {
-    sampleData = new byte[0];
+    sampleData = Util.EMPTY_BYTE_ARRAY;
     sampleTimesUs.clear();
     sampleFlags.clear();
     sampleStartOffsets.clear();