Adds OnChildWindowVisibilityChanged to ui::WindowObserver

ash/mus/bridge/mus_layout_manager_adapter.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/mus/bridge/mus_layout_manager_adapter.h"
 
 #include "ash/common/wm_layout_manager.h"
 #include "ash/mus/bridge/wm_window_mus.h"
 #include "services/ui/public/cpp/window.h"
 
 namespace ash {
 namespace mus {
 
-MusLayoutManagerAdapter::ChildWindowObserver::ChildWindowObserver(
-    MusLayoutManagerAdapter* adapter)
-    : adapter_(adapter) {}
-
-MusLayoutManagerAdapter::ChildWindowObserver::~ChildWindowObserver() {}
-
-void MusLayoutManagerAdapter::ChildWindowObserver::OnWindowVisibilityChanged(
-    ui::Window* window) {
-  adapter_->layout_manager_->OnChildWindowVisibilityChanged(
-      WmWindowMus::Get(window), window->visible());
-}
-
 MusLayoutManagerAdapter::MusLayoutManagerAdapter(
     ui::Window* window,
     std::unique_ptr<WmLayoutManager> layout_manager)
     : window_(window),
-      child_window_observer_(this),
       layout_manager_(std::move(layout_manager)) {
   window_->AddObserver(this);
-  for (ui::Window* child : window_->children())
-    child->AddObserver(&child_window_observer_);
 }
 
 MusLayoutManagerAdapter::~MusLayoutManagerAdapter() {
-  for (ui::Window* child : window_->children())
-    child->RemoveObserver(&child_window_observer_);
-
   window_->RemoveObserver(this);
 }
 
 void MusLayoutManagerAdapter::OnTreeChanging(const TreeChangeParams& params) {
   if (params.old_parent == window_) {
     layout_manager_->OnWillRemoveWindowFromLayout(
         WmWindowMus::Get(params.target));
   }
 }
 
 void MusLayoutManagerAdapter::OnTreeChanged(const TreeChangeParams& params) {
-  if (params.new_parent == window_) {
+  if (params.new_parent == window_)
     layout_manager_->OnWindowAddedToLayout(WmWindowMus::Get(params.target));
-    params.target->AddObserver(&child_window_observer_);
-  } else if (params.old_parent == window_) {
-    params.target->RemoveObserver(&child_window_observer_);
+  else if (params.old_parent == window_)
     layout_manager_->OnWindowRemovedFromLayout(WmWindowMus::Get(params.target));
-  }
 }
 
 void MusLayoutManagerAdapter::OnWindowBoundsChanged(
     ui::Window* window,
     const gfx::Rect& old_bounds,
     const gfx::Rect& new_bounds) {
   layout_manager_->OnWindowResized();
 }
 
+void MusLayoutManagerAdapter::OnChildWindowVisibilityChanged(ui::Window* window,
+                                                             bool visible) {
+  layout_manager_->OnChildWindowVisibilityChanged(WmWindowMus::Get(window),
+                                                  visible);
+}
+
 }  // namespace mus
 }  // namespace ash