Nix GetRootWindowController, use RootWindowController::ForWindow.

ash/root_window_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/root_window_controller.h"
 
 #include <algorithm>
 #include <queue>
 #include <vector>
 
@@ skipping 293 matching lines @@
 void RootWindowController::CreateForSecondaryDisplay(AshWindowTreeHost* host) {
   RootWindowController* controller = new RootWindowController(host, nullptr);
   controller->Init(RootWindowType::SECONDARY);
 }
 
 // static
 RootWindowController* RootWindowController::ForWindow(
     const aura::Window* window) {
   DCHECK(window);
   CHECK(Shell::HasInstance());
-  return GetRootWindowController(window->GetRootWindow());
+  return GetRootWindowSettings(window->GetRootWindow())->controller;
 }
 
 // static
 RootWindowController* RootWindowController::ForTargetRootWindow() {
   CHECK(Shell::HasInstance());
-  return GetRootWindowController(Shell::GetRootWindowForNewWindows());
+  return ForWindow(Shell::GetRootWindowForNewWindows());
 }
 
 void RootWindowController::ConfigureWidgetInitParamsForContainer(
     views::Widget* widget,
     int shell_container_id,
     views::Widget::InitParams* init_params) {
   init_params->parent = GetContainer(shell_container_id);
 }
 
 aura::WindowTreeHost* RootWindowController::GetHost() {
@@ skipping 735 matching lines @@
   shelf_->UpdateVisibilityState();
 }
 
 void RootWindowController::OnTouchHudProjectionToggled(bool enabled) {
   if (enabled)
     EnableTouchHudProjection();
   else
     DisableTouchHudProjection();
 }
 
-RootWindowController* GetRootWindowController(const aura::Window* root_window) {
-  return root_window ? GetRootWindowSettings(root_window)->controller : nullptr;
-}
-
 }  // namespace ash