Revert "chromeos: Move files in //ash/common to //ash, part 3"

ash/wm_window_user_data.h

-// 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.
-
-#ifndef ASH_WM_WINDOW_USER_DATA_H_
-#define ASH_WM_WINDOW_USER_DATA_H_
-
-#include <map>
-#include <memory>
-#include <utility>
-
-#include "ash/wm_window.h"
-#include "base/macros.h"
-#include "ui/aura/window.h"
-#include "ui/aura/window_observer.h"
-
-namespace ash {
-
-// WmWindowUserData provides a way to associate arbitrary objects with a
-// WmWindow. WmWindowUserData owns the data, deleting it either when
-// WmWindowUserData is deleted, or when the window the data is associated with
-// is destroyed (from aura::WindowObserver::OnWindowDestroying()).
-template <typename UserData>
-class WmWindowUserData : public aura::WindowObserver {
- public:
-  WmWindowUserData() {}
-
-  ~WmWindowUserData() override { clear(); }
-
-  void clear() {
-    for (auto& pair : window_to_data_)
-      pair.first->aura_window()->RemoveObserver(this);
-    window_to_data_.clear();
-  }
-
-  // Sets the data associated with window. This destroys any existing data.
-  // |data| may be null.
-  void Set(WmWindow* window, std::unique_ptr<UserData> data) {
-    if (!data) {
-      if (window_to_data_.erase(window))
-        window->aura_window()->RemoveObserver(this);
-      return;
-    }
-    if (window_to_data_.count(window) == 0u)
-      window->aura_window()->AddObserver(this);
-    window_to_data_[window] = std::move(data);
-  }
-
-  // Returns the data associated with the window, or null if none set. The
-  // returned object is owned by WmWindowUserData.
-  UserData* Get(WmWindow* window) {
-    auto it = window_to_data_.find(window);
-    return it == window_to_data_.end() ? nullptr : it->second.get();
-  }
-
-  // Returns the set of windows with data associated with them.
-  std::set<WmWindow*> GetWindows() {
-    std::set<WmWindow*> windows;
-    for (auto& pair : window_to_data_)
-      windows.insert(pair.first);
-    return windows;
-  }
-
- private:
-  // aura::WindowObserver:
-  void OnWindowDestroying(aura::Window* window) override {
-    window->RemoveObserver(this);
-    window_to_data_.erase(WmWindow::Get(window));
-  }
-
-  std::map<WmWindow*, std::unique_ptr<UserData>> window_to_data_;
-
-  DISALLOW_COPY_AND_ASSIGN(WmWindowUserData);
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_WINDOW_USER_DATA_H_