DO NOT MERGE: SF: Fix a race between layer creation and apply transaction

Between commitCreatedLayers and applyTransactions in the main
thread, the client could create a new layer and queue a transaction.
This will mean a layer transaction can be applied before the layer
can be committed.

Fix this by flushing the transactions to be applied before
committing any new layers.

Test: presubmit
Fixes: b/262336014
Change-Id: I9987614ade29456453de3610782a645ea9db0892
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 46f0e6b..ea0e780 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -770,6 +770,9 @@
             REQUIRES(mStateLock);
     // flush pending transaction that was presented after desiredPresentTime.
     bool flushTransactionQueues(int64_t vsyncId);
+
+    std::vector<TransactionState> flushTransactions();
+
     // Returns true if there is at least one transaction that needs to be flushed
     bool transactionFlushNeeded();
 
@@ -818,7 +821,8 @@
                                size_t totalTXapplied) const;
     bool stopTransactionProcessing(const std::unordered_set<sp<IBinder>, SpHash<IBinder>>&
                                            applyTokensWithUnsignaledTransactions) const;
-    bool applyTransactions(std::vector<TransactionState>& transactions, int64_t vsyncId)
+    bool applyTransactions(std::vector<TransactionState>& transactions, int64_t vsyncId);
+    bool applyTransactionsLocked(std::vector<TransactionState>& transactions, int64_t vsyncId)
             REQUIRES(mStateLock);
     uint32_t setDisplayStateLocked(const DisplayState& s) REQUIRES(mStateLock);
     uint32_t addInputWindowCommands(const InputWindowCommands& inputWindowCommands)