Nix GetRootWindowController, use RootWindowController::ForWindow.

ash/wm/drag_window_resizer_unittest.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/wm/drag_window_resizer.h"
 
 #include "ash/display/mouse_cursor_event_filter.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ skipping 596 matching lines @@
     EXPECT_EQ(2.0f, cursor_test_api.GetCurrentCursor().device_scale_factor());
     resizer->CompleteDrag();
     EXPECT_EQ(2.0f, cursor_test_api.GetCurrentCursor().device_scale_factor());
   }
 
   // Move window from the root window with 2.0 device scale factor to the root
   // window with 1.0 device scale factor.
   {
     // Make sure the window is on the default container first.
     aura::Window* default_container =
-        GetRootWindowController(root_windows[1])
+        RootWindowController::ForWindow(root_windows[1])
             ->GetContainer(kShellWindowId_DefaultContainer);
     default_container->AddChild(window_.get());
     window_->SetBoundsInScreen(
         gfx::Rect(600, 0, 50, 60),
         display::Screen::GetScreen()->GetDisplayNearestWindow(root_windows[1]));
     EXPECT_EQ(root_windows[1], window_->GetRootWindow());
     // Grab (0, 0) of the window.
     std::unique_ptr<WindowResizer> resizer(
         CreateDragWindowResizer(window_.get(), gfx::Point(), HTCAPTION));
     EXPECT_EQ(2.0f, cursor_test_api.GetCurrentCursor().device_scale_factor());
@@ skipping 113 matching lines @@
     ASSERT_TRUE(resizer.get());
     resizer->Drag(CalculateDragPoint(*resizer, 399, 200), 0);
     EXPECT_TRUE(TestIfMouseWarpsAt(gfx::Point(399, 200)));
     EXPECT_EQ("401,200",
               aura::Env::GetInstance()->last_mouse_location().ToString());
     resizer->CompleteDrag();
   }
 }
 
 }  // namespace ash