Merge "Properly abort queued transitions during clean-up" into main

            mOnStartCollect = onStartCollect;

            mLegacySync = legacySync;

        }

        boolean isAborted(BLASTSyncEngine syncEngine) {

            return mTransition == null ? syncEngine.getSyncSet(mLegacySync.mSyncId) == null

                    : mTransition.isAborted();

        }

    }

    private final ArrayList<QueuedTransition> mQueuedTransitions = new ArrayList<>();

            // Post this so that the now-playing transition logic isn't interrupted.

            mAtm.mH.post(() -> {

                synchronized (mAtm.mGlobalLock) {

                    // The transition/sync may be aborted if the transition player died.

                    if (queued.isAborted(mSyncEngine)) return;

                    queued.mOnStartCollect.onCollectStarted(true /* deferred */);

                }

            });