NuPlayer: fix av discontinuity race

Assumption:
  NuPlayer must see both (a/v) discontinuities before resuming.

Example issue:
  Suppose we're changing the video track, so the video source queues a
  DISCONTINUITY_FORMATCHANGE, and the audio source queues a DISCONTINUITY_NONE.
  Consider this sequence of events without this change:
    1. audio discontinuity seen by player
    2. mFlushingAudio = FLUSHED
    3. video discontinuity seen by player
    4. mFlushingAudio != NONE so no performScanSources is queued
    5. video decoding shuts down without being restarted

Bug: 15153976
Change-Id: I659550d9c0f883828103142abead857f576f25b1

1 files changed, 8 insertions, 7 deletions

diff --git a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
index adc5f33..58d0138 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
@@ -1230,14 +1230,15 @@ status_t NuPlayer::feedDecoderInputData(bool audio, const sp<AMessage> &msg) {
                 mTimeDiscontinuityPending =
                     mTimeDiscontinuityPending || timeChange;
 
+                if (mFlushingAudio == NONE && mFlushingVideo == NONE) {
+                    // And we'll resume scanning sources once we're done
+                    // flushing.
+                    mDeferredActions.push_front(
+                            new SimpleAction(
+                                &NuPlayer::performScanSources));
+                }
+
                 if (formatChange || timeChange) {
-                    if (mFlushingAudio == NONE && mFlushingVideo == NONE) {
-                        // And we'll resume scanning sources once we're done
-                        // flushing.
-                        mDeferredActions.push_front(
-                                new SimpleAction(
-                                    &NuPlayer::performScanSources));
-                    }
 
                     sp<AMessage> newFormat = mSource->getFormat(audio);
                     sp<Decoder> &decoder = audio ? mAudioDecoder : mVideoDecoder;