mash: Migrate ScopedTargetRootWindow to //ash/common

ash/common/wm_shell.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_SHELL_H_
 #define ASH_COMMON_WM_SHELL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 20 matching lines @@
 class AccessibilityDelegate;
 class BrightnessControlDelegate;
 class DisplayInfo;
 class FocusCycler;
 class KeyboardBrightnessControlDelegate;
 class KeyboardUI;
 class MaximizeModeController;
 class MruWindowTracker;
 class NewWindowDelegate;
 class ScopedDisableInternalMouseAndKeyboard;
+class ScopedRootWindowForNewWindows;
 class SessionStateDelegate;
 class ShelfDelegate;
 class ShelfModel;
 class ShellDelegate;
 class ShellObserver;
 class SystemTrayDelegate;
 class SystemTrayNotifier;
 class ToastManager;
 class WindowCycleController;
 class WindowCycleEventFilter;
@@ skipping 92 matching lines @@
   virtual WmWindow* GetPrimaryRootWindow() = 0;
 
   // Returns the root window for the specified display.
   virtual WmWindow* GetRootWindowForDisplayId(int64_t display_id) = 0;
 
   // Returns the root window that newly created windows should be added to.
   // NOTE: this returns the root, newly created window should be added to the
   // appropriate container in the returned window.
   virtual WmWindow* GetRootWindowForNewWindows() = 0;
 
+  // Allows a temporary override of the result of GetRootWindowForNewWindows().
+  virtual std::unique_ptr<ScopedRootWindowForNewWindows>
+  CreateScopedRootWindowForNewWindows(WmWindow* root) = 0;
+
   // Retuns the display info associated with |display_id|.
   // TODO(msw): Remove this when DisplayManager has been moved. crbug.com/622480
   virtual const DisplayInfo& GetDisplayInfo(int64_t display_id) const = 0;
 
   // Matches that of DisplayManager::IsActiveDisplayId().
   // TODO: Remove this when DisplayManager has been moved. crbug.com/622480
   virtual bool IsActiveDisplayId(int64_t display_id) const = 0;
 
   // Returns true if the first window shown on first run should be
   // unconditionally maximized, overriding the heuristic that normally chooses
@@ skipping 189 matching lines @@
   bool simulate_modal_window_open_for_testing_ = false;
 
 #if defined(OS_CHROMEOS)
   std::unique_ptr<LogoutConfirmationController> logout_confirmation_controller_;
 #endif
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_SHELL_H_