Remove WmLookup.

ash/aura/wm_lookup_aura.cc

Index: ash/aura/wm_lookup_aura.cc
diff --git a/ash/aura/wm_lookup_aura.cc b/ash/aura/wm_lookup_aura.cc
deleted file mode 100644
index 6a690b8d2645b913bbae7b6d748f49861d259534..0000000000000000000000000000000000000000
--- a/ash/aura/wm_lookup_aura.cc
+++ /dev/null
@@ -1,36 +0,0 @@
-// 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/aura/wm_lookup_aura.h"
-
-#include "ash/common/wm_layout_manager.h"
-#include "ash/common/wm_window.h"
-#include "ash/display/window_tree_host_manager.h"
-#include "ash/root_window_controller.h"
-#include "ash/shell.h"
-#include "ui/views/widget/widget.h"
-
-namespace ash {
-
-WmLookupAura::WmLookupAura() {
-  WmLookup::Set(this);
-}
-
-WmLookupAura::~WmLookupAura() {
-  WmLookup::Set(nullptr);
-}
-
-RootWindowController* WmLookupAura::GetRootWindowControllerWithDisplayId(
-    int64_t id) {
-  aura::Window* root_window = Shell::GetInstance()
-                                  ->window_tree_host_manager()
-                                  ->GetRootWindowForDisplayId(id);
-  return root_window ? RootWindowController::ForWindow(root_window) : nullptr;
-}
-
-WmWindow* WmLookupAura::GetWindowForWidget(views::Widget* widget) {
-  return WmWindow::Get(widget->GetNativeWindow());
-}
-
-}  // namespace ash