Makes display roots be destroyed by client

services/ui/ws/window_manager_client_unittest.cc

 // Copyright 2014 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 <stddef.h>
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 39 matching lines @@
   bool OnWmSetProperty(
       Window* window,
       const std::string& name,
       std::unique_ptr<std::vector<uint8_t>>* new_data) override {
     return true;
   }
   Window* OnWmCreateTopLevelWindow(
       std::map<std::string, std::vector<uint8_t>>* properties) override {
     return nullptr;
   }
+  void OnWmDisplayRemoved(ui::Window* window) override {}
   void OnWmClientJankinessChanged(const std::set<Window*>& client_windows,
                                   bool janky) override {}
   void OnWmNewDisplay(Window* window,
                       const display::Display& display) override {}
   void OnWmPerformMoveLoop(Window* window,
                            mojom::MoveLoopSource source,
                            const gfx::Point& cursor_location,
                            const base::Callback<void(bool)>& on_done) override {
   }
   void OnWmCancelMoveLoop(Window* window) override {}
@@ skipping 1059 matching lines @@
   ASSERT_TRUE(window_in_wm);
 
   // Change the bounds in the wm, and make sure the child sees it.
   window_in_wm->SetBounds(gfx::Rect(1, 11, 12, 101));
   ASSERT_TRUE(WaitForBoundsToChange(window_in_second_client));
   EXPECT_EQ(gfx::Rect(1, 11, 12, 101), window_in_second_client->bounds());
 }
 
 }  // namespace ws
 }  // namespace ui