Add MediaCodecSelector.getPassthroughDecoderInfo.

Issue: #1518
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=122157463

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

@@ -170,7 +170,7 @@ public class MediaCodecAudioTrackRenderer extends MediaCodecTrackRenderer implem
     if (!MimeTypes.isAudio(mimeType)) {
       return FORMAT_UNSUPPORTED_TYPE;
     }
-    if (allowPassthrough(mimeType) && mediaCodecSelector.getPassthroughDecoderName() != null) {
+    if (allowPassthrough(mimeType) && mediaCodecSelector.getPassthroughDecoderInfo() != null) {
       return ADAPTIVE_NOT_SEAMLESS | FORMAT_HANDLED;
     }
     // TODO[REFACTOR]: If requiresSecureDecryption then we should probably also check that the
@@ -194,10 +194,10 @@ public class MediaCodecAudioTrackRenderer extends MediaCodecTrackRenderer implem
   protected DecoderInfo getDecoderInfo(MediaCodecSelector mediaCodecSelector, Format format,
       boolean requiresSecureDecoder) throws DecoderQueryException {
     if (allowPassthrough(format.sampleMimeType)) {
-      String passthroughDecoderName = mediaCodecSelector.getPassthroughDecoderName();
+      DecoderInfo passthroughDecoderInfo = mediaCodecSelector.getPassthroughDecoderInfo();
-      if (passthroughDecoderName != null) {
+      if (passthroughDecoderInfo != null) {
         passthroughEnabled = true;
-        return new DecoderInfo(passthroughDecoderName);
+        return passthroughDecoderInfo;
       }
     }
     passthroughEnabled = false;

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

@@ -29,11 +29,6 @@ public interface MediaCodecSelector {
    */
   MediaCodecSelector DEFAULT = new MediaCodecSelector() {
 
-    /**
-     * The name for the raw (passthrough) decoder OMX component.
-     */
-    private static final String RAW_DECODER_NAME = "OMX.google.raw.decoder";
-
     @Override
     public DecoderInfo getDecoderInfo(String mimeType, boolean requiresSecureDecoder)
         throws DecoderQueryException {
@@ -41,9 +36,8 @@ public interface MediaCodecSelector {
     }
 
     @Override
-    public String getPassthroughDecoderName() throws DecoderQueryException {
+    public DecoderInfo getPassthroughDecoderInfo() throws DecoderQueryException {
-      // TODO: Return null if the raw decoder doesn't exist.
+      return MediaCodecUtil.getPassthroughDecoderInfo();
-      return RAW_DECODER_NAME;
     }
 
   };
@@ -53,20 +47,18 @@ public interface MediaCodecSelector {
    *
    * @param mimeType The mime type for which a decoder is required.
    * @param requiresSecureDecoder Whether a secure decoder is required.
-   * @return A {@link DecoderInfo} describing the decoder to instantiate, or null if no suitable
+   * @return A {@link DecoderInfo} describing the decoder, or null if no suitable decoder exists.
-   *     decoder exists.
    * @throws DecoderQueryException Thrown if there was an error querying decoders.
    */
   DecoderInfo getDecoderInfo(String mimeType, boolean requiresSecureDecoder)
       throws DecoderQueryException;
 
   /**
-   * Gets the name of a decoder suitable for audio passthrough.
+   * Selects a decoder to instantiate for audio passthrough.
    *
-   * @return The name of a decoder suitable for audio passthrough, or null if no suitable decoder
+   * @return A {@link DecoderInfo} describing the decoder, or null if no suitable decoder exists.
-   *     exists.
    * @throws DecoderQueryException Thrown if there was an error querying decoders.
    */
-  String getPassthroughDecoderName() throws DecoderQueryException;
+  DecoderInfo getPassthroughDecoderInfo() throws DecoderQueryException;
 
 }

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

@@ -52,6 +52,8 @@ public final class MediaCodecUtil {
   }
 
   private static final String TAG = "MediaCodecUtil";
+  private static final DecoderInfo PASSTHROUGH_DECODER_INFO =
+      new DecoderInfo("OMX.google.raw.decoder", null);
 
   private static final HashMap<CodecKey, List<DecoderInfo>> decoderInfosCache = new HashMap<>();
 
@@ -79,12 +81,22 @@ public final class MediaCodecUtil {
   }
 
   /**
-   * Returns information about the decoder that will be used for a given mime type.
+   * Returns information about a decoder suitable for audio passthrough.
+   **
+   * @return A {@link DecoderInfo} describing the decoder, or null if no suitable decoder exists.
+   */
+  public static DecoderInfo getPassthroughDecoderInfo() {
+    // TODO: Return null if the raw decoder doesn't exist.
+    return PASSTHROUGH_DECODER_INFO;
+  }
+
+  /**
+   * Returns information about the preferred decoder for a given mime type.
    *
    * @param mimeType The mime type.
    * @param secure Whether the decoder is required to support secure decryption. Always pass false
    *     unless secure decryption really is required.
-   * @return Information about the decoder that will be used, or null if no decoder exists.
+   * @return A {@link DecoderInfo} describing the decoder, or null if no suitable decoder exists.
    */
   public static DecoderInfo getDecoderInfo(String mimeType, boolean secure)
       throws DecoderQueryException {