Reland of "Mustash: Ensure surfaces submitted to Mus by WM and embedders contain Surfaces with embe…

services/ui/ws/display.cc

 // Copyright 2015 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 "services/ui/ws/display.h"
 
 #include <set>
 #include <utility>
 #include <vector>
 
@@ skipping 253 matching lines @@
 }
 
 display::Display Display::GetDisplay() {
   return ToDisplay();
 }
 
 ServerWindow* Display::GetRootWindow() {
   return root_.get();
 }
 
+ServerWindow* Display::GetActiveRootWindow() {
+  WindowManagerDisplayRoot* display_root = GetActiveWindowManagerDisplayRoot();
+  if (display_root)
+    return display_root->root();
+  return nullptr;
+}
+
 void Display::OnAcceleratedWidgetAvailable() {
   display_manager()->OnDisplayAcceleratedWidgetAvailable(this);
   InitWindowManagerDisplayRoots();
 }
 
 bool Display::IsInHighContrastMode() {
   return window_server_->IsActiveUserInHighContrastMode();
 }
 
 void Display::OnEvent(const ui::Event& event) {
@@ skipping 101 matching lines @@
 }
 
 void Display::OnWindowManagerWindowTreeFactoryReady(
     WindowManagerWindowTreeFactory* factory) {
   if (!binding_)
     CreateWindowManagerDisplayRootFromFactory(factory);
 }
 
 }  // namespace ws
 }  // namespace ui