diff --git a/services/surfaceflinger/ActivePictureUpdater.h b/services/surfaceflinger/ActivePictureUpdater.h
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+++ b/services/surfaceflinger/ActivePictureUpdater.h
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+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <vector>
+
+#include <android/gui/ActivePicture.h>
+
+namespace android {
+
+class Layer;
+class LayerFE;
+struct CompositionResult;
+
+// Keeps track of active pictures - layers that are undergoing picture processing.
+class ActivePictureUpdater {
+public:
+    // Called for each visible layer when SurfaceFlinger finishes composing.
+    void onLayerComposed(const Layer& layer, const LayerFE& layerFE,
+                         const CompositionResult& result);
+
+    // Update internals and return whether the set of active pictures have changed.
+    bool updateAndHasChanged();
+
+    // The current set of active pictures.
+    const std::vector<gui::ActivePicture>& getActivePictures() const;
+
+private:
+    std::vector<gui::ActivePicture> mOldActivePictures;
+    std::vector<gui::ActivePicture> mNewActivePictures;
+};
+
+} // namespace android