Clear remoteSyncPoints for detached layers.

When a layer gets detached, the remote sync points should get removed so
the buffer layer isn't waiting for that transaction to get applied.
Detached layers can never apply transactions so the buffer layer will
wait forever for the transaction to get applied.

Test: Steps from bug
Test: ChildLayerTest.DetachChildrenWithDeferredTransaction
Fixes: 132125338
Change-Id: I333855a70a40152457f39e953bc7300d696c7c62
diff --git a/services/surfaceflinger/BufferLayer.cpp b/services/surfaceflinger/BufferLayer.cpp
index a2b6ab6..9d72399 100644
--- a/services/surfaceflinger/BufferLayer.cpp
+++ b/services/surfaceflinger/BufferLayer.cpp
@@ -545,6 +545,12 @@
         if (headFrameNumber >= point->getFrameNumber() && headFenceSignaled &&
             presentTimeIsCurrent) {
             point->setFrameAvailable();
+            sp<Layer> requestedSyncLayer = point->getRequestedSyncLayer();
+            if (requestedSyncLayer) {
+                // Need to update the transaction flag to ensure the layer's pending transaction
+                // gets applied.
+                requestedSyncLayer->setTransactionFlags(eTransactionNeeded);
+            }
         }
     }
 }