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.cpp b/services/surfaceflinger/RegionSamplingThread.cpp
index 8dd3b0f..6e64e0a 100644
--- a/services/surfaceflinger/RegionSamplingThread.cpp
+++ b/services/surfaceflinger/RegionSamplingThread.cpp
@@ -40,6 +40,7 @@
 
 #include "DisplayDevice.h"
 #include "DisplayRenderArea.h"
+#include "FrontEnd/LayerCreationArgs.h"
 #include "Layer.h"
 #include "Scheduler/VsyncController.h"
 #include "SurfaceFlinger.h"
@@ -129,12 +130,12 @@
     }
 }
 
-void RegionSamplingThread::addListener(const Rect& samplingArea, const wp<Layer>& stopLayer,
+void RegionSamplingThread::addListener(const Rect& samplingArea, uint32_t stopLayerId,
                                        const sp<IRegionSamplingListener>& listener) {
     sp<IBinder> asBinder = IInterface::asBinder(listener);
     asBinder->linkToDeath(sp<DeathRecipient>::fromExisting(this));
     std::lock_guard lock(mSamplingMutex);
-    mDescriptors.emplace(wp<IBinder>(asBinder), Descriptor{samplingArea, stopLayer, listener});
+    mDescriptors.emplace(wp<IBinder>(asBinder), Descriptor{samplingArea, stopLayerId, listener});
 }
 
 void RegionSamplingThread::removeListener(const sp<IRegionSamplingListener>& listener) {
@@ -291,8 +292,8 @@
             if (stopLayerFound) return;
 
             // Likewise if we just found a stop layer, set the flag and abort
-            for (const auto& [area, stopLayer, listener] : descriptors) {
-                if (layer == stopLayer.promote().get()) {
+            for (const auto& [area, stopLayerId, listener] : descriptors) {
+                if (stopLayerId != UNASSIGNED_LAYER_ID && layer->getSequence() == stopLayerId) {
                     stopLayerFound = true;
                     return;
                 }
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;
     };
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cfebec7..8fefcb1 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1580,9 +1580,10 @@
 
     // LayerHandle::getLayer promotes the layer object in a binder thread but we will not destroy
     // the layer here since the caller has a strong ref to the layer's handle.
-    // TODO (b/238781169): replace layer with layer id
-    const wp<Layer> stopLayer = LayerHandle::getLayer(stopLayerHandle);
-    mRegionSamplingThread->addListener(samplingArea, stopLayer, listener);
+    const sp<Layer> stopLayer = LayerHandle::getLayer(stopLayerHandle);
+    mRegionSamplingThread->addListener(samplingArea,
+                                       stopLayer ? stopLayer->getSequence() : UNASSIGNED_LAYER_ID,
+                                       listener);
     return NO_ERROR;
 }