commit 1c5481ea27625ae9ecb2f386bc115d479fdf50c4
author Robert Carr <racarr@google.com> Mon Jul 01 14:42:27 2019 -0700
committer Robert Carr <racarr@google.com> Mon Jul 01 15:04:38 2019 -0700
tree 233efcedeb306471eaa8425cbeb19d597f3c2af7
parent 37131865d03edbbeb7e5a59dbbf3f75b19b7641a

SurfaceFlinger: Hide Z order relatives when relativeOf is hiddenByPolicy.

Now that we are using relative Z for the SurfaceView background we
encounter yet another edge case. During Surface preservation we reparent
the SurfaceView from one WindowStateAnimator to a second. When we reparent
it we hide the old surface and show the new one. However at this time
the background is still relative to the OLD surface, which is Z ordered
on top of the new Surface. To fix this we ensure that if a layers relative
Z parent is hidden by policy the layer is also invisible.

Bug: 136061599
Test: TransactionTest#HideRelativeParentHidesLayer
Change-Id: I941fb9060dab79dba89300a5c86d6ea1a69f577d

services/surfaceflinger/Layer.cpp

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index bda7e43..1318bc0 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1231,6 +1231,14 @@
     if (parent != nullptr && parent->isHiddenByPolicy()) {
         return true;
     }
+    if (usingRelativeZ(LayerVector::StateSet::Drawing)) {
+        auto zOrderRelativeOf = mDrawingState.zOrderRelativeOf.promote();
+        if (zOrderRelativeOf != nullptr) {
+            if (zOrderRelativeOf->isHiddenByPolicy()) {
+                return true;
+            }
+        }
+    }
     return s.flags & layer_state_t::eLayerHidden;
 }
 
@@ -1612,7 +1620,7 @@
     return mDrawingState.z;
 }
 
-bool Layer::usingRelativeZ(LayerVector::StateSet stateSet) {
+bool Layer::usingRelativeZ(LayerVector::StateSet stateSet) const {
     const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
     const State& state = useDrawing ? mDrawingState : mCurrentState;
     return state.zOrderRelativeOf != nullptr;