Fix bug in MCVR where dummySurface is released but surface isn't nulled

The fix for Issue: #8776 was to release and null-out dummySurface if
it doesn't match the security level of the decoder. But it's possible
that this.surface is already set to this.dummySurface, in which case we
must also null out this.surface otherwise we will later try and re-use
the old, released DummySurface instance.

This logic already exists in MCVR#onReset, so I pulled it into a
releaseDummySurface() helper function.

Issue: #9476
#minor-release
PiperOrigin-RevId: 399420476

RELEASENOTES.md

@@ -13,6 +13,10 @@
         `GlUtil.glAssertionsEnabled` instead.
     *   Move `Player.addListener(EventListener)` and
         `Player.removeListener(EventListener)` out of `Player` into subclasses.
+*   Video:
+    *   Fix bug in `MediaCodecVideoRenderer` that resulted in re-using a
+        released `Surface` when playing without an app-provided `Surface`
+        ([#9476](https://github.com/google/ExoPlayer/issues/9476)).
 *   Android 12 compatibility:
     *   Keep `DownloadService` started and in the foreground whilst waiting for
         requirements to be met on Android 12. This is necessary due to new

library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java

@@ -495,11 +495,7 @@ protected void onReset() {
       super.onReset();
     } finally {
       if (dummySurface != null) {
-        if (surface == dummySurface) {
-          surface = null;
-        }
-        dummySurface.release();
-        dummySurface = null;
+        releaseDummySurface();
       }
     }
   }
@@ -618,8 +614,7 @@ protected MediaCodecAdapter.Configuration getMediaCodecConfiguration(
       float codecOperatingRate) {
     if (dummySurface != null && dummySurface.secure != codecInfo.secure) {
       // We can't re-use the current DummySurface instance with the new decoder.
-      dummySurface.release();
-      dummySurface = null;
+      releaseDummySurface();
     }
     String codecMimeType = codecInfo.codecMimeType;
     codecMaxValues = getCodecMaxValues(codecInfo, format, getStreamFormats());
@@ -1178,6 +1173,14 @@ private boolean shouldUseDummySurface(MediaCodecInfo codecInfo) {
         && (!codecInfo.secure || DummySurface.isSecureSupported(context));
   }
 
+  private void releaseDummySurface() {
+    if (surface == dummySurface) {
+      surface = null;
+    }
+    dummySurface.release();
+    dummySurface = null;
+  }
+
   private void setJoiningDeadlineMs() {
     joiningDeadlineMs =
         allowedJoiningTimeMs > 0