mash: Migrate ScopedTargetRootWindow to //ash/common

ash/mus/accelerators/accelerator_controller_registrar.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 "ash/mus/accelerators/accelerator_controller_registrar.h"
 
 #include <limits>
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/accelerators/accelerator_router.h"
@@ skipping 67 matching lines @@
     // is called for *all* key events, where as this is only called for
     // registered accelerators. This means the previous accelerator isn't the
     // same as it was in ash. We need to figure out exactly what is needed of
     // previous accelerator so that we can either register for the right set of
     // accelerators, or make WS send the previous accelerator.
     // http://crbug.com/630683.
     accelerator_controller->accelerator_history()->StoreCurrentAccelerator(
         accelerator);
     WmWindow* target_window = WmShell::Get()->GetFocusedWindow();
     if (!target_window)
-      target_window = WmShell::Get()->GetRootWindowForNewWindows();
+      target_window = WmShell::Get()->root_window_for_new_windows();
     DCHECK(target_window);
     return router_->ProcessAccelerator(target_window, *(event.AsKeyEvent()),
                                        accelerator)
                ? ui::mojom::EventResult::HANDLED
                : ui::mojom::EventResult::UNHANDLED;
   }
   DCHECK_EQ(GetAcceleratorLocalId(id), ids.post_id);
   // NOTE: for post return value doesn't really matter.
   return WmShell::Get()->accelerator_controller()->Process(accelerator)
              ? ui::mojom::EventResult::HANDLED
@@ skipping 61 matching lines @@
   // Common case is we never wrap once, so this is typically cheap. Additionally
   // we expect there not to be too many accelerators.
   while (ids_.count(next_id_) > 0)
     ++next_id_;
   ids_.insert(next_id_);
   return next_id_++;
 }
 
 }  // namespace mus
 }  // namespace ash