Fix Vts drawLayers function for async renderengine change

Bug: 180657548
Test: this
Change-Id: I8980d843599fe8b8195f6a1b8540b5d13528ac4b
diff --git a/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp b/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
index f78dda2..fe59a9d 100644
--- a/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
+++ b/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
@@ -60,7 +60,6 @@
 
 void TestRenderEngine::drawLayers() {
     base::unique_fd bufferFence;
-    base::unique_fd readyFence;
 
     std::vector<const renderengine::LayerSettings*> compositionLayerPointers;
     compositionLayerPointers.reserve(mCompositionLayers.size());
@@ -71,8 +70,10 @@
                    });
     auto texture = std::make_shared<renderengine::ExternalTexture>(
             mGraphicBuffer, *mRenderEngine, renderengine::ExternalTexture::Usage::WRITEABLE);
-    mRenderEngine->drawLayers(mDisplaySettings, compositionLayerPointers, texture, true,
-                              std::move(bufferFence), &readyFence);
+    auto [status, readyFence] = mRenderEngine
+                                        ->drawLayers(mDisplaySettings, compositionLayerPointers,
+                                                     texture, true, std::move(bufferFence))
+                                        .get();
     int fd = readyFence.release();
     if (fd != -1) {
         ASSERT_EQ(0, sync_wait(fd, -1));