SubtitleExtractor: mark the limit of the input buffer

Before this change, the SubtitleExtractor did not mark the limit
of the input buffer, thus the SubtitleDecoder attempted to decode
more bytes. If the subtitle file had a new line at the end, this
bug would make the SubtitleDecoder append an line break after the
last subtitle.

PiperOrigin-RevId: 402523039

library/extractor/src/main/java/com/google/android/exoplayer2/text/SubtitleExtractor.java

@@ -212,6 +212,7 @@ public class SubtitleExtractor implements Extractor {
       }
       inputBuffer.ensureSpaceForWrite(bytesRead);
       inputBuffer.data.put(subtitleData.getData(), /* offset= */ 0, bytesRead);
+      inputBuffer.data.limit(bytesRead);
       subtitleDecoder.queueInputBuffer(inputBuffer);
       @Nullable SubtitleOutputBuffer outputBuffer = subtitleDecoder.dequeueOutputBuffer();
       while (outputBuffer == null) {

library/extractor/src/test/java/com/google/android/exoplayer2/text/SubtitleExtractorTest.java

@@ -44,7 +44,7 @@ public class SubtitleExtractorTest {
           + "This is the second subtitle.\n"
           + "\n"
           + "00:02.600 --> 00:04.567\n"
-          + "This is the third subtitle.";
+          + "This is the third subtitle.\n";
 
   @Test
   public void extractor_outputsCues() throws Exception {