Revert of [M55] Generalize layer mirroring for phantom windows

ash/wm/drag_window_controller.cc

Index: ash/wm/drag_window_controller.cc
diff --git a/ash/wm/drag_window_controller.cc b/ash/wm/drag_window_controller.cc
index 6e4add8c34a89fd676240ce7fb536172a48aed08..fb6bc25cf677e44f7384d95fd00d60a68bc4538a 100644
--- a/ash/wm/drag_window_controller.cc
+++ b/ash/wm/drag_window_controller.cc
@@ -8,6 +8,7 @@
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shell_window_ids.h"
+#include "ash/common/wm/forwarding_layer_delegate.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
@@ -32,7 +33,9 @@
 
 // This keeps track of the drag window's state. It creates/destroys/updates
 // bounds and opacity based on the current bounds.
-class DragWindowController::DragWindowDetails : public aura::WindowDelegate {
+class DragWindowController::DragWindowDetails
+    : public aura::WindowDelegate,
+      public ::wm::LayerDelegateFactory {
  public:
   DragWindowDetails(const display::Display& display,
                     aura::Window* original_window)
@@ -112,12 +115,14 @@
 
   void RecreateWindowLayers(aura::Window* original_window) {
     DCHECK(!layer_owner_.get());
-    layer_owner_ = ::wm::MirrorLayers(original_window, true /* sync_bounds */);
+    layer_owner_ = ::wm::RecreateLayers(original_window, this);
     // Place the layer at (0, 0) of the DragWindowController's window.
     gfx::Rect layer_bounds = layer_owner_->root()->bounds();
     layer_bounds.set_origin(gfx::Point(0, 0));
     layer_owner_->root()->SetBounds(layer_bounds);
     layer_owner_->root()->SetVisible(false);
+    // Detach it from the current container.
+    layer_owner_->root()->parent()->Remove(layer_owner_->root());
   }
 
   void SetOpacity(const aura::Window* original_window, float opacity) {
@@ -125,6 +130,16 @@
     ui::ScopedLayerAnimationSettings scoped_setter(layer->GetAnimator());
     layer->SetOpacity(opacity);
     layer_owner_->root()->SetOpacity(1.0f);
+  }
+
+  // aura::WindowDelegate:
+  ui::LayerDelegate* CreateDelegate(ui::Layer* foo, ui::Layer* layer) override {
+    if (!layer || !layer->delegate())
+      return nullptr;
+    wm::ForwardingLayerDelegate* new_delegate =
+        new wm::ForwardingLayerDelegate(foo, layer);
+    delegates_.push_back(base::WrapUnique(new_delegate));
+    return new_delegate;
   }
 
   // aura::WindowDelegate:
@@ -161,6 +176,8 @@
   aura::Window* drag_window_ = nullptr;  // Owned by the container.
 
   aura::Window* original_window_ = nullptr;
+
+  std::vector<std::unique_ptr<wm::ForwardingLayerDelegate>> delegates_;
 
   // The copy of window_->layer() and its descendants.
   std::unique_ptr<ui::LayerTreeOwner> layer_owner_;