Removes code using mus client lib

ui/views/mus/drag_drop_client_mus.cc

-// Copyright 2016 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 "ui/views/mus/drag_drop_client_mus.h"
-
-#include <map>
-#include <string>
-#include <vector>
-
-#include "base/message_loop/message_loop.h"
-#include "base/run_loop.h"
-#include "services/ui/public/cpp/window.h"
-#include "ui/aura/mus/os_exchange_data_provider_mus.h"
-#include "ui/aura/window.h"
-
-namespace views {
-namespace {
-
-DragDropClientMus* current_dragging_client = nullptr;
-
-}  // namespace
-
-DragDropClientMus::DragDropClientMus(ui::Window* ui_window)
-    : ui_window_(ui_window) {}
-
-DragDropClientMus::~DragDropClientMus() {}
-
-int DragDropClientMus::StartDragAndDrop(
-    const ui::OSExchangeData& data,
-    aura::Window* root_window,
-    aura::Window* source_window,
-    const gfx::Point& screen_location,
-    int drag_operations,
-    ui::DragDropTypes::DragEventSource source) {
-  std::map<std::string, std::vector<uint8_t>> drag_data =
-      static_cast<const aura::OSExchangeDataProviderMus&>(data.provider())
-          .GetData();
-
-  // TODO(erg): Right now, I'm passing the cursor_location, but maybe I want to
-  // pass OSExchangeData::GetDragImageOffset() instead?
-
-  bool success = false;
-  gfx::Point cursor_location = screen_location;
-  uint32_t action_taken = ui::mojom::kDropEffectNone;
-  current_dragging_client = this;
-  ui_window_->PerformDragDrop(
-      drag_data, drag_operations, cursor_location,
-      *data.provider().GetDragImage().bitmap(),
-      base::Bind(&DragDropClientMus::OnMoveLoopEnd, base::Unretained(this),
-                 &success, &action_taken));
-
-  base::MessageLoop* loop = base::MessageLoop::current();
-  base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
-  base::RunLoop run_loop;
-
-  runloop_quit_closure_ = run_loop.QuitClosure();
-  run_loop.Run();
-  current_dragging_client = nullptr;
-
-  return action_taken;
-}
-
-void DragDropClientMus::DragCancel() {
-  ui_window_->CancelDragDrop();
-}
-
-bool DragDropClientMus::IsDragDropInProgress() {
-  return !!current_dragging_client;
-}
-
-void DragDropClientMus::OnMoveLoopEnd(bool* out_success,
-                                      uint32_t* out_action,
-                                      bool in_success,
-                                      uint32_t in_action) {
-  *out_success = in_success;
-  *out_action = in_action;
-  runloop_quit_closure_.Run();
-}
-
-}  // namespace views