Revert of [M55] Generalize layer mirroring for phantom windows

ui/wm/core/window_util.cc

Index: ui/wm/core/window_util.cc
diff --git a/ui/wm/core/window_util.cc b/ui/wm/core/window_util.cc
index 39fa162969b966ccbbee172c43f5c6cde6b85117..0dc44d50da993b8a289b2f4ce15f04b240662d9c 100644
--- a/ui/wm/core/window_util.cc
+++ b/ui/wm/core/window_util.cc
@@ -4,7 +4,6 @@
 
 #include "ui/wm/core/window_util.h"
 
-#include "base/memory/ptr_util.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_tree_owner.h"
@@ -17,7 +16,9 @@
 // cloned children to |parent|.
 //
 // WARNING: It is assumed that |parent| is ultimately owned by a LayerTreeOwner.
-void CloneChildren(ui::Layer* to_clone, ui::Layer* parent) {
+void CloneChildren(ui::Layer* to_clone,
+                   ui::Layer* parent,
+                   wm::LayerDelegateFactory* factory) {
   typedef std::vector<ui::Layer*> Layers;
   // Make a copy of the children since RecreateLayer() mutates it.
   Layers children(to_clone->children());
@@ -25,26 +26,14 @@
     ui::LayerOwner* owner = (*i)->owner();
     ui::Layer* old_layer = owner ? owner->RecreateLayer().release() : NULL;
     if (old_layer) {
+      if (factory && owner->layer()->delegate())
+        old_layer->set_delegate(
+            factory->CreateDelegate(old_layer, owner->layer()));
       parent->Add(old_layer);
       // RecreateLayer() moves the existing children to the new layer. Create a
       // copy of those.
-      CloneChildren(owner->layer(), old_layer);
+      CloneChildren(owner->layer(), old_layer, factory);
     }
-  }
-}
-
-// Invokes Mirror() on all the children of |to_mirror|, adding the newly cloned
-// children to |parent|.
-//
-// WARNING: It is assumed that |parent| is ultimately owned by a LayerTreeOwner.
-void MirrorChildren(ui::Layer* to_mirror,
-                    ui::Layer* parent,
-                    bool sync_bounds) {
-  for (auto* child : to_mirror->children()) {
-    child->set_sync_bounds(sync_bounds);
-    ui::Layer* mirror = child->Mirror().release();
-    parent->Add(mirror);
-    MirrorChildren(child, mirror, sync_bounds);
   }
 }
 
@@ -96,18 +85,19 @@
   return client ? client->GetToplevelWindow(window) : NULL;
 }
 
-std::unique_ptr<ui::LayerTreeOwner> RecreateLayers(ui::LayerOwner* root) {
-  DCHECK(root->OwnsLayer());
-  auto old_layer = base::MakeUnique<ui::LayerTreeOwner>(root->RecreateLayer());
-  CloneChildren(root->layer(), old_layer->root());
+std::unique_ptr<ui::LayerTreeOwner> RecreateLayers(
+    ui::LayerOwner* root,
+    LayerDelegateFactory* factory) {
+  std::unique_ptr<ui::LayerTreeOwner> old_layer(
+      new ui::LayerTreeOwner(root->RecreateLayer().release()));
+  if (old_layer->root()) {
+    if (factory) {
+      old_layer->root()->set_delegate(
+          factory->CreateDelegate(old_layer->root(), root->layer()));
+    }
+    CloneChildren(root->layer(), old_layer->root(), factory);
+  }
   return old_layer;
-}
-
-std::unique_ptr<ui::LayerTreeOwner> MirrorLayers(
-    ui::LayerOwner* root, bool sync_bounds) {
-  auto mirror = base::MakeUnique<ui::LayerTreeOwner>(root->layer()->Mirror());
-  MirrorChildren(root->layer(), mirror->root(), sync_bounds);
-  return mirror;
 }
 
 aura::Window* GetTransientParent(aura::Window* window) {