Revert of Deletes mojo::Callback

components/mus/ws/window_tree.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 "components/mus/ws/window_tree.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 13 matching lines @@
 #include "components/mus/ws/server_window_observer.h"
 #include "components/mus/ws/user_display_manager.h"
 #include "components/mus/ws/window_manager_state.h"
 #include "components/mus/ws/window_server.h"
 #include "components/mus/ws/window_tree_binding.h"
 #include "ui/display/display.h"
 #include "ui/platform_window/mojo/ime_type_converters.h"
 #include "ui/platform_window/text_input_state.h"
 
 using mojo::Array;
+using mojo::Callback;
 using mojo::InterfaceRequest;
 using mojo::String;
 
 namespace mus {
 namespace ws {
 
 class TargetedEvent : public ServerWindowObserver {
  public:
   TargetedEvent(ServerWindow* target, const ui::Event& event)
       : target_(target), event_(ui::Event::Clone(event)) {
@@ skipping 1068 matching lines @@
     success = true;
     Operation op(this, window_server_, OperationType::REORDER_WINDOW);
     window->Reorder(relative_window, direction);
     window_server_->ProcessWindowReorder(window, relative_window, direction);
   }
   client()->OnChangeCompleted(change_id, success);
 }
 
 void WindowTree::GetWindowTree(
     Id window_id,
-    const base::Callback<void(Array<mojom::WindowDataPtr>)>& callback) {
+    const Callback<void(Array<mojom::WindowDataPtr>)>& callback) {
   std::vector<const ServerWindow*> windows(
       GetWindowTree(ClientWindowId(window_id)));
   callback.Run(WindowsToWindowDatas(windows));
 }
 
 void WindowTree::SetCapture(uint32_t change_id, Id window_id) {
   client()->OnChangeCompleted(change_id, SetCapture(ClientWindowId(window_id)));
 }
 
 void WindowTree::ReleaseCapture(uint32_t change_id, Id window_id) {
@@ skipping 374 matching lines @@
 }
 
 bool WindowTree::IsWindowRootOfAnotherTreeForAccessPolicy(
     const ServerWindow* window) const {
   WindowTree* tree = window_server_->GetTreeWithRoot(window);
   return tree && tree != this;
 }
 
 }  // namespace ws
 }  // namespace mus