Remove use of legacy layers from TransactionApplicationTest

Legacy layers are no longer used in production, this
changes the unit tests to use requestedlayerstate
directly.

Flag: EXEMPT removing flagged code
Test: presubmit
Bug: 330785038
Change-Id: I50e3a5e15d9b97ec04e49af2b6b4aab77ed17e7a
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index fa7a515..9e62f38 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -620,6 +620,18 @@
         mFlinger->mNewLayers.emplace_back(std::move(layer));
     }
 
+    // Used to add a layer before updateLayerSnapshots is called.
+    // Must have transactionsFlushed enabled for the new layer to be updated.
+    void addLayer(uint32_t layerId) {
+        std::scoped_lock<std::mutex> lock(mFlinger->mCreatedLayersLock);
+        LayerCreationArgs args(std::make_optional(layerId));
+        args.flinger = this->mFlinger.get();
+        auto layer = std::make_unique<frontend::RequestedLayerState>(args);
+        auto legacyLayer = sp<Layer>::make(args);
+        injectLegacyLayer(legacyLayer);
+        mFlinger->mNewLayers.emplace_back(std::move(layer));
+    }
+
     /* ------------------------------------------------------------------------
      * Read-only access to private data to assert post-conditions.
      */