Remove redundant MetadataDecoder.canDecode method

This is no longer needed as MetadataDecoderFactory
figures out which decoder should be used.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=144999613

library/src/main/java/com/google/android/exoplayer2/metadata/MetadataDecoder.java

@@ -21,14 +21,6 @@ package com.google.android.exoplayer2.metadata;
 public interface MetadataDecoder {
 
   /**
-   * Checks whether the decoder supports a given mime type.
-   *
-   * @param mimeType A metadata mime type.
-   * @return Whether the mime type is supported.
-   */
-  boolean canDecode(String mimeType);
-
-  /**
    * Decodes a {@link Metadata} element from the provided input buffer.
    *
    * @param inputBuffer The input buffer to decode.

library/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoder.java

@@ -18,7 +18,6 @@ package com.google.android.exoplayer2.metadata.emsg;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
-import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
@@ -32,11 +31,6 @@ import java.util.Arrays;
 public final class EventMessageDecoder implements MetadataDecoder {
 
   @Override
-  public boolean canDecode(String mimeType) {
-    return MimeTypes.APPLICATION_EMSG.equals(mimeType);
-  }
-
-  @Override
   public Metadata decode(MetadataInputBuffer inputBuffer) {
     ByteBuffer buffer = inputBuffer.data;
     byte[] data = buffer.array();

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

@@ -20,7 +20,6 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
-import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import java.io.UnsupportedEncodingException;
@@ -52,11 +51,6 @@ public final class Id3Decoder implements MetadataDecoder {
   private static final int ID3_TEXT_ENCODING_UTF_8 = 3;
 
   @Override
-  public boolean canDecode(String mimeType) {
-    return mimeType.equals(MimeTypes.APPLICATION_ID3);
-  }
-
-  @Override
   public Metadata decode(MetadataInputBuffer inputBuffer) {
     ByteBuffer buffer = inputBuffer.data;
     return decode(buffer.array(), buffer.limit());

library/src/main/java/com/google/android/exoplayer2/metadata/scte35/SpliceInfoDecoder.java

@@ -15,12 +15,10 @@
  */
 package com.google.android.exoplayer2.metadata.scte35;
 
-import android.text.TextUtils;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataDecoderException;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
-import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import java.nio.ByteBuffer;
@@ -45,11 +43,6 @@ public final class SpliceInfoDecoder implements MetadataDecoder {
   }
 
   @Override
-  public boolean canDecode(String mimeType) {
-    return TextUtils.equals(mimeType, MimeTypes.APPLICATION_SCTE35);
-  }
-
-  @Override
   public Metadata decode(MetadataInputBuffer inputBuffer) throws MetadataDecoderException {
     ByteBuffer buffer = inputBuffer.data;
     byte[] data = buffer.array();