Surface synchronization: Don't gutter translucent windows

ash/mus/top_level_window_factory.cc

 // Copyright 2017 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/top_level_window_factory.h"
 
 #include "ash/mus/disconnected_app_handler.h"
 #include "ash/mus/frame/detached_title_area_renderer.h"
 #include "ash/mus/non_client_frame_controller.h"
 #include "ash/mus/property_util.h"
@@ skipping 208 matching lines @@
   if (focusable_iter != properties->end()) {
     bool can_focus = mojo::ConvertTo<bool>(focusable_iter->second);
     window_manager->window_tree_client()->SetCanFocus(window, can_focus);
     NonClientFrameController* non_client_frame_controller =
         NonClientFrameController::Get(window);
     if (non_client_frame_controller)
       non_client_frame_controller->set_can_activate(can_focus);
     // No need to persist this value.
     properties->erase(focusable_iter);
   }
+
+  auto translucent_iter =
+      properties->find(ui::mojom::WindowManager::kTranslucent_InitProperty);
+  if (translucent_iter != properties->end()) {
+    bool translucent = mojo::ConvertTo<bool>(translucent_iter->second);
+    window->SetTransparent(translucent);
+    // No need to persist this value.
+    properties->erase(translucent_iter);
+  }
+
   return window;
 }
 
 }  // namespace mus
 }  // namespace ash