Revert of Window prerequisites for ShelfWindowWatcher panel support.

ui/views/mus/desktop_window_tree_host_mus.cc

Index: ui/views/mus/desktop_window_tree_host_mus.cc
diff --git a/ui/views/mus/desktop_window_tree_host_mus.cc b/ui/views/mus/desktop_window_tree_host_mus.cc
index d2f236b0e615a10c3cddd769d5efc0a5ce1a9e86..478dfb93fa70c09ad16107f3db46aa0226626030 100644
--- a/ui/views/mus/desktop_window_tree_host_mus.cc
+++ b/ui/views/mus/desktop_window_tree_host_mus.cc
@@ -14,7 +14,6 @@
 #include "ui/views/corewm/tooltip_aura.h"
 #include "ui/views/mus/mus_client.h"
 #include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
-#include "ui/views/widget/native_widget_aura.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/wm/core/window_util.h"
 #include "ui/wm/public/activation_client.h"
@@ -305,7 +304,14 @@
 
 void DesktopWindowTreeHostMus::SetWindowIcons(const gfx::ImageSkia& window_icon,
                                               const gfx::ImageSkia& app_icon) {
-  NativeWidgetAura::AssignIconToAuraWindow(window(), window_icon, app_icon);
+  if (window_icon.isNull() && app_icon.isNull()) {
+    window()->ClearProperty(aura::client::kWindowIconKey);
+    return;
+  }
+
+  window()->SetProperty(
+      aura::client::kWindowIconKey,
+      new gfx::ImageSkia(!window_icon.isNull() ? window_icon : app_icon));
 }
 
 void DesktopWindowTreeHostMus::InitModalType(ui::ModalType modal_type) {