Remove FormatHolder.includesDrmSession

With the Renderer migration, this is officially unnecessary, and
should always be true for supported encrypted content.

PiperOrigin-RevId: 295584542

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

@@ -23,11 +23,6 @@
  */
 public final class FormatHolder {
 
-  /** Whether the {@link #format} setter also sets the {@link #drmSession} field. */
-  // TODO: Remove once all Renderers and MediaSources have migrated to the new DRM model [Internal
-  // ref: b/129764794].
-  public boolean includesDrmSession;
-
   /** An accompanying context for decrypting samples in the format. */
   @Nullable public DrmSession<?> drmSession;
 
@@ -36,7 +31,6 @@ public final class FormatHolder {
 
   /** Clears the holder. */
   public void clear() {
-    includesDrmSession = false;
     drmSession = null;
     format = null;
   }

library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java

@@ -783,7 +783,6 @@ private void onFormatResult(Format newFormat, FormatHolder outputFormatHolder) {
       return;
     }
     @Nullable DrmInitData newDrmInitData = newFormat.drmInitData;
-    outputFormatHolder.includesDrmSession = true;
     outputFormatHolder.drmSession = currentDrmSession;
     if (!isFirstFormat && Util.areEqual(oldDrmInitData, newDrmInitData)) {
       // Nothing to do.