Add @CallSuper annotations in SimpleDecoder

The implementation can't work properly unless these methods are called by
subclasses, so annotate them to require calling the super implementation when
overriding.

PiperOrigin-RevId: 265017433

library/core/src/main/java/com/google/android/exoplayer2/decoder/SimpleDecoder.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.decoder;
 
+import androidx.annotation.CallSuper;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.Assertions;
@@ -125,6 +126,7 @@ public abstract class SimpleDecoder<
    *
    * @param outputBuffer The output buffer being released.
    */
+  @CallSuper
   protected void releaseOutputBuffer(O outputBuffer) {
     synchronized (lock) {
       releaseOutputBufferInternal(outputBuffer);
@@ -150,6 +152,7 @@ public abstract class SimpleDecoder<
     }
   }
 
+  @CallSuper
   @Override
   public void release() {
     synchronized (lock) {