media: Destroy VTVDA session on the decoder thread.

media/gpu/vt_video_decode_accelerator_mac.cc

Index: media/gpu/vt_video_decode_accelerator_mac.cc
diff --git a/media/gpu/vt_video_decode_accelerator_mac.cc b/media/gpu/vt_video_decode_accelerator_mac.cc
index e179548de9bcfbc483f1f696cd9b3e02a5b99bef..f79b2da9118d6d4bce9ff7e891ee36e11c402c2a 100644
--- a/media/gpu/vt_video_decode_accelerator_mac.cc
+++ b/media/gpu/vt_video_decode_accelerator_mac.cc
@@ -815,8 +815,13 @@ void VTVideoDecodeAccelerator::FlushTask(TaskType type) {
 
   FinishDelayedFrames();
 
-  // Always queue a task, even if FinishDelayedFrames() fails, so that
-  // destruction always completes.
+  if (type == TASK_DESTROY && session_) {
+    // Destroy the decoding session before returning from the decoder thread.
+    VTDecompressionSessionInvalidate(session_);
+    session_.reset();
+  }
+
+  // Queue a task even if flushing fails, so that destruction always completes.
   gpu_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&VTVideoDecodeAccelerator::FlushDone, weak_this_, type));