From 1812c76943e71c2c7c9d319aac605232c86ec853 Mon Sep 17 00:00:00 2001
From: Vadim Caen <caen@google.com>
Date: Mon, 12 Aug 2019 11:38:22 +0200
Subject: [PATCH] Add a root layer in DisplayContent

To enable surface animation on the overlay layer and the windowing
layer, a leash needs to be created on top of them, but because they have
no parent, there is nothing to reattache them to after the leash is
destroyed.

Adding a root layer as a container layer enbale us to workaround this
issue.

Test: presubmit and manually with the new rotation animation running on
with SurfaceAnimator (in upcoming CL)
Bug: 131727512

Change-Id: I156a7a479a055341a67eafcc203ee2c83d88a30e
---
 .../com/android/server/wm/DisplayContent.java     | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 5d42d18a97ac4..50ee9b9c808f5 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -942,14 +942,17 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         final SurfaceControl.Builder b = mWmService.makeSurfaceBuilder(mSession)
                 .setOpaque(true)
                 .setContainerLayer();
-        mWindowingLayer = b.setName("Display Root").build();
-        mOverlayLayer = b.setName("Display Overlays").build();
+        mSurfaceControl = b.setName("Root").setContainerLayer().build();
+        mWindowingLayer = b.setName("Display Windows").setParent(mSurfaceControl).build();
+        mOverlayLayer = b.setName("Display Overlays").setParent(mSurfaceControl).build();
 
-        getPendingTransaction().setLayer(mWindowingLayer, 0)
-                .setLayerStack(mWindowingLayer, mDisplayId)
+        getPendingTransaction()
+                .setLayer(mSurfaceControl, 0)
+                .setLayerStack(mSurfaceControl, mDisplayId)
+                .show(mSurfaceControl)
+                .setLayer(mWindowingLayer, 0)
                 .show(mWindowingLayer)
                 .setLayer(mOverlayLayer, 1)
-                .setLayerStack(mOverlayLayer, mDisplayId)
                 .show(mOverlayLayer);
         getPendingTransaction().apply();
 
@@ -4880,7 +4883,7 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
             mPortalWindowHandle = createPortalWindowHandle(sc.toString());
         }
         getPendingTransaction().setInputWindowInfo(sc, mPortalWindowHandle)
-                .reparent(mWindowingLayer, sc).reparent(mOverlayLayer, sc);
+                .reparent(mSurfaceControl, sc);
     }
 
     /**