Replace WmWindowObserver with aura::WindowObserver.

ash/common/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_COMMON_WM_WINDOW_USER_DATA_H_
 #define ASH_COMMON_WM_WINDOW_USER_DATA_H_
 
 #include <map>
 #include <memory>
 #include <utility>
 
 #include "ash/common/wm_window.h"
-#include "ash/common/wm_window_observer.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 WmWindowObserver::OnWindowDestroying()).
+// is destroyed (from aura::WindowObserver::OnWindowDestroying()).
 template <typename UserData>
-class WmWindowUserData : public WmWindowObserver {
+class WmWindowUserData : public aura::WindowObserver {
  public:
   WmWindowUserData() {}
 
   ~WmWindowUserData() override { clear(); }
 
   void clear() {
     for (auto& pair : window_to_data_)
-      pair.first->RemoveObserver(this);
+      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->RemoveObserver(this);
+        window->aura_window()->RemoveObserver(this);
       return;
     }
     if (window_to_data_.count(window) == 0u)
-      window->AddObserver(this);
+      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:
-  // WmWindowObserver:
-  void OnWindowDestroying(WmWindow* window) override {
+  // aura::WindowObserver:
+  void OnWindowDestroying(aura::Window* window) override {
     window->RemoveObserver(this);
-    window_to_data_.erase(window);
+    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_COMMON_WM_WINDOW_USER_DATA_H_