SF: Use layer id for region sampling stop layer

Cleanup before layer refbase removal. We
can lookup the stop layer by using a unique id.

Bug: 238781169
Test: presubmit
Change-Id: I33da6899adebc33c814656591f78187f08c53e80
diff --git a/services/surfaceflinger/RegionSamplingThread.h b/services/surfaceflinger/RegionSamplingThread.h
index 686b4b1..b62b15c 100644
--- a/services/surfaceflinger/RegionSamplingThread.h
+++ b/services/surfaceflinger/RegionSamplingThread.h
@@ -26,6 +26,7 @@
 
 #include <chrono>
 #include <condition_variable>
+#include <cstdint>
 #include <mutex>
 #include <thread>
 #include <unordered_map>
@@ -73,7 +74,7 @@
 
     // Add a listener to receive luma notifications. The luma reported via listener will
     // report the median luma for the layers under the stopLayerHandle, in the samplingArea region.
-    void addListener(const Rect& samplingArea, const wp<Layer>& stopLayer,
+    void addListener(const Rect& samplingArea, uint32_t stopLayerId,
                      const sp<IRegionSamplingListener>& listener);
     // Remove the listener to stop receiving median luma notifications.
     void removeListener(const sp<IRegionSamplingListener>& listener);
@@ -87,7 +88,7 @@
 private:
     struct Descriptor {
         Rect area = Rect::EMPTY_RECT;
-        wp<Layer> stopLayer;
+        uint32_t stopLayerId;
         sp<IRegionSamplingListener> listener;
     };