Add nullness annotations to a few more files

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=212644046

library/core/src/main/java/com/google/android/exoplayer2/ExoPlaybackException.java

@@ -64,25 +64,27 @@ public final class ExoPlaybackException extends Exception {
    */
   public final int rendererIndex;
 
+  private final Throwable cause;
+
   /**
-   * Creates an instance of type {@link #TYPE_RENDERER}.
+   * Creates an instance of type {@link #TYPE_SOURCE}.
    *
    * @param cause The cause of the failure.
-   * @param rendererIndex The index of the renderer in which the failure occurred.
    * @return The created instance.
    */
-  public static ExoPlaybackException createForRenderer(Exception cause, int rendererIndex) {
-    return new ExoPlaybackException(TYPE_RENDERER, null, cause, rendererIndex);
+  public static ExoPlaybackException createForSource(IOException cause) {
+    return new ExoPlaybackException(TYPE_SOURCE, cause, C.INDEX_UNSET);
   }
 
   /**
-   * Creates an instance of type {@link #TYPE_SOURCE}.
+   * Creates an instance of type {@link #TYPE_RENDERER}.
    *
    * @param cause The cause of the failure.
+   * @param rendererIndex The index of the renderer in which the failure occurred.
    * @return The created instance.
    */
-  public static ExoPlaybackException createForSource(IOException cause) {
-    return new ExoPlaybackException(TYPE_SOURCE, null, cause, C.INDEX_UNSET);
+  public static ExoPlaybackException createForRenderer(Exception cause, int rendererIndex) {
+    return new ExoPlaybackException(TYPE_RENDERER, cause, rendererIndex);
   }
 
   /**
@@ -92,13 +94,13 @@ public final class ExoPlaybackException extends Exception {
    * @return The created instance.
    */
   /* package */ static ExoPlaybackException createForUnexpected(RuntimeException cause) {
-    return new ExoPlaybackException(TYPE_UNEXPECTED, null, cause, C.INDEX_UNSET);
+    return new ExoPlaybackException(TYPE_UNEXPECTED, cause, C.INDEX_UNSET);
   }
 
-  private ExoPlaybackException(@Type int type, String message, Throwable cause,
-      int rendererIndex) {
-    super(message, cause);
+  private ExoPlaybackException(@Type int type, Throwable cause, int rendererIndex) {
+    super(cause);
     this.type = type;
+    this.cause = cause;
     this.rendererIndex = rendererIndex;
   }
 
@@ -109,7 +111,7 @@ public final class ExoPlaybackException extends Exception {
    */
   public IOException getSourceException() {
     Assertions.checkState(type == TYPE_SOURCE);
-    return (IOException) getCause();
+    return (IOException) cause;
   }
 
   /**
@@ -119,7 +121,7 @@ public final class ExoPlaybackException extends Exception {
    */
   public Exception getRendererException() {
     Assertions.checkState(type == TYPE_RENDERER);
-    return (Exception) getCause();
+    return (Exception) cause;
   }
 
   /**
@@ -129,7 +131,7 @@ public final class ExoPlaybackException extends Exception {
    */
   public RuntimeException getUnexpectedException() {
     Assertions.checkState(type == TYPE_UNEXPECTED);
-    return (RuntimeException) getCause();
+    return (RuntimeException) cause;
   }
 
 }

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp3/VbriSeeker.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.extractor.mp3;
 
+import android.support.annotation.Nullable;
 import android.util.Log;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.extractor.MpegAudioHeader;
@@ -42,8 +43,8 @@ import com.google.android.exoplayer2.util.Util;
    * @return A {@link VbriSeeker} for seeking in the stream, or {@code null} if the required
    *     information is not present.
    */
-  public static VbriSeeker create(long inputLength, long position, MpegAudioHeader mpegAudioHeader,
-      ParsableByteArray frame) {
+  public static @Nullable VbriSeeker create(
+      long inputLength, long position, MpegAudioHeader mpegAudioHeader, ParsableByteArray frame) {
     frame.skipBytes(10);
     int numFrames = frame.readInt();
     if (numFrames <= 0) {

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp3/XingSeeker.java

@@ -15,10 +15,12 @@
  */
 package com.google.android.exoplayer2.extractor.mp3;
 
+import android.support.annotation.Nullable;
 import android.util.Log;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.extractor.MpegAudioHeader;
 import com.google.android.exoplayer2.extractor.SeekPoint;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 
@@ -38,12 +40,12 @@ import com.google.android.exoplayer2.util.Util;
    * @param position The position of the start of this frame in the stream.
    * @param mpegAudioHeader The MPEG audio header associated with the frame.
    * @param frame The data in this audio frame, with its position set to immediately after the
-   *    'Xing' or 'Info' tag.
+   *     'Xing' or 'Info' tag.
    * @return A {@link XingSeeker} for seeking in the stream, or {@code null} if the required
    *     information is not present.
    */
-  public static XingSeeker create(long inputLength, long position, MpegAudioHeader mpegAudioHeader,
-      ParsableByteArray frame) {
+  public static @Nullable XingSeeker create(
+      long inputLength, long position, MpegAudioHeader mpegAudioHeader, ParsableByteArray frame) {
     int samplesPerFrame = mpegAudioHeader.samplesPerFrame;
     int sampleRate = mpegAudioHeader.sampleRate;
 
@@ -85,16 +87,21 @@ import com.google.android.exoplayer2.util.Util;
    */
   private final long dataSize;
   /**
-   * Entries are in the range [0, 255], but are stored as long integers for convenience.
+   * Entries are in the range [0, 255], but are stored as long integers for convenience. Null if the
+   * table of contents was missing from the header, in which case seeking is not be supported.
    */
-  private final long[] tableOfContents;
+  private final @Nullable long[] tableOfContents;
 
   private XingSeeker(long dataStartPosition, int xingFrameSize, long durationUs) {
     this(dataStartPosition, xingFrameSize, durationUs, C.LENGTH_UNSET, null);
   }
 
-  private XingSeeker(long dataStartPosition, int xingFrameSize, long durationUs, long dataSize,
-      long[] tableOfContents) {
+  private XingSeeker(
+      long dataStartPosition,
+      int xingFrameSize,
+      long durationUs,
+      long dataSize,
+      @Nullable long[] tableOfContents) {
     this.dataStartPosition = dataStartPosition;
     this.xingFrameSize = xingFrameSize;
     this.durationUs = durationUs;
@@ -121,6 +128,7 @@ import com.google.android.exoplayer2.util.Util;
       scaledPosition = 256;
     } else {
       int prevTableIndex = (int) percent;
+      long[] tableOfContents = Assertions.checkNotNull(this.tableOfContents);
       double prevScaledPosition = tableOfContents[prevTableIndex];
       double nextScaledPosition = prevTableIndex == 99 ? 256 : tableOfContents[prevTableIndex + 1];
       // Linearly interpolate between the two scaled positions.
@@ -140,6 +148,7 @@ import com.google.android.exoplayer2.util.Util;
     if (!isSeekable() || positionOffset <= xingFrameSize) {
       return 0L;
     }
+    long[] tableOfContents = Assertions.checkNotNull(this.tableOfContents);
     double scaledPosition = (positionOffset * 256d) / dataSize;
     int prevTableIndex = Util.binarySearchFloor(tableOfContents, (long) scaledPosition, true, true);
     long prevTimeUs = getTimeUsForTableIndex(prevTableIndex);