Nix GetRootWindowController, use RootWindowController::ForWindow.

ash/magnifier/magnification_controller.cc

 // Copyright (c) 2012 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/magnifier/magnification_controller.h"
 
 #include <memory>
 #include <utility>
 
 #include "ash/accelerators/accelerator_controller.h"
@@ skipping 361 matching lines @@
   settings.SetPreemptionStrategy(
       ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
   settings.SetTweenType(tween_type);
   settings.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(duration_in_ms));
 
   display::Display display =
       display::Screen::GetScreen()->GetDisplayNearestWindow(root_window_);
   std::unique_ptr<RootWindowTransformer> transformer(
       CreateRootWindowTransformerForDisplay(root_window_, display));
-  GetRootWindowController(root_window_)
+  RootWindowController::ForWindow(root_window_)
       ->ash_host()
       ->SetRootWindowTransformer(std::move(transformer));
 
   if (duration_in_ms > 0)
     is_on_animation_ = true;
 
   return true;
 }
 
 void MagnificationControllerImpl::StartOrStopScrollIfNecessary() {
@@ skipping 501 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
 // static
 MagnificationController* MagnificationController::CreateInstance() {
   return new MagnificationControllerImpl();
 }
 
 }  // namespace ash