Renames WmWindowUserData and converts to using aura

ash/wm/screen_pinning_controller.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_SCREEN_PINNING_CONTROLLER_H_
 #define ASH_WM_SCREEN_PINNING_CONTROLLER_H_
 
 #include <memory>
 #include <vector>
 
 #include "ash/display/window_tree_host_manager.h"
 #include "base/macros.h"
+#include "ui/aura/window_tracker.h"
 
 namespace ash {
 
-class WindowDimmer;
 class WindowTreeHostManager;
 class WmWindow;
 
-template <typename UserData>
-class WmWindowUserData;
-
 // Handles pinned state.
 class ScreenPinningController : public WindowTreeHostManager::Observer {
  public:
   explicit ScreenPinningController(
       WindowTreeHostManager* window_tree_host_manager);
   ~ScreenPinningController() override;
 
   // Sets a pinned window. It is not allowed to call this when there already
   // is a pinned window.
   void SetPinnedWindow(WmWindow* pinned_window);
@@ skipping 40 matching lines @@
   // Creates a WindowDimmer for |container| and places it in |window_dimmers_|.
   // Returns the window from WindowDimmer.
   WmWindow* CreateWindowDimmer(WmWindow* container);
 
   // WindowTreeHostManager::Observer:
   void OnDisplayConfigurationChanged() override;
 
   // Pinned window should be on top in the parent window.
   WmWindow* pinned_window_ = nullptr;
 
-  // Owns the WindowDimmers. There is one WindowDimmer for the parent of
-  // |pinned_window_| and one for each display other than the display
-  // |pinned_window_| is on.
-  std::unique_ptr<WmWindowUserData<WindowDimmer>> window_dimmers_;
+  // Maintains the set of aura::Windows that have a WindowDimmer installed on
+  // them. There is one WindowDimmer for the parent of |pinned_window_| and one
+  // for each display other than the display |pinned_window_| is on.
+  aura::WindowTracker windows_with_dimmers_;
 
   // Set true only when restacking done by this controller.
   bool in_restacking_ = false;
 
   // Keep references to remove this as a observer.
   // While this controller is alive, it needs to be ensured that the instances
   // refered from the pointers should be alive.
   WindowTreeHostManager* window_tree_host_manager_;
 
   // Window observers to translate events for the window to this controller.
   std::unique_ptr<PinnedContainerWindowObserver>
       pinned_container_window_observer_;
   std::unique_ptr<PinnedContainerChildWindowObserver>
       pinned_container_child_window_observer_;
   std::unique_ptr<SystemModalContainerWindowObserver>
       system_modal_container_window_observer_;
   std::unique_ptr<SystemModalContainerChildWindowObserver>
       system_modal_container_child_window_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenPinningController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_SCREEN_PINNING_CONTROLLER_H_