Add layerStack field to DisplayInfo

screenrecord utility requires display layer stack in order to record
external displays.

Bug: 140814450
Bug: 136165419
Test: screenrecord --display-id <physical-display-id>
Change-Id: I1ec562e4df2db684eb9f216bd4439bb267a7d3e3
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 4361a94..cc34f50 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -874,11 +874,15 @@
                 info.viewportW = uint32_t(viewport.getWidth());
                 info.viewportH = uint32_t(viewport.getHeight());
             }
+            info.layerStack = display->getLayerStack();
         } else {
             // TODO: where should this value come from?
             static const int TV_DENSITY = 213;
             info.density = TV_DENSITY / 160.0f;
             info.orientation = 0;
+
+            const auto display = getDisplayDeviceLocked(displayToken);
+            info.layerStack = display->getLayerStack();
         }
 
         info.xdpi = xdpi;