Fix dirty region updates if a layer becomes invisible

Ensure we correctly update the output layer's
dirty region if a layer becomes invisible.

Flag: EXEMPT bug fix
Bug: 330785038
Test: presubmit
Change-Id: I38c501320316babe6ba12c49d9d542c4f6103aaa
diff --git a/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.cpp b/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.cpp
index c874db3..ac15b92 100644
--- a/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.cpp
+++ b/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.cpp
@@ -1265,6 +1265,12 @@
     }
 }
 
+void LayerSnapshotBuilder::forEachSnapshot(const ConstVisitor& visitor) const {
+    for (auto& snapshot : mSnapshots) {
+        visitor(*snapshot);
+    }
+}
+
 void LayerSnapshotBuilder::forEachInputSnapshot(const ConstVisitor& visitor) const {
     for (int i = mNumInterestingSnapshots - 1; i >= 0; i--) {
         LayerSnapshot& snapshot = *mSnapshots[(size_t)i];
diff --git a/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.h b/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.h
index 207e23a..486cb33 100644
--- a/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.h
+++ b/services/surfaceflinger/FrontEnd/LayerSnapshotBuilder.h
@@ -91,6 +91,9 @@
     // snapshots in z-order
     void forEachSnapshot(const Visitor& visitor, const ConstPredicate& predicate);
 
+    // Visit each snapshot
+    void forEachSnapshot(const ConstVisitor& visitor) const;
+
     // Visit each snapshot interesting to input reverse z-order
     void forEachInputSnapshot(const ConstVisitor& visitor) const;