Moves couple of WmShell methods to standalone functions

ash/common/accelerators/accelerator_commands.cc

 // Copyright 2013 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/common/accelerators/accelerator_commands.h"
 
 #include "ash/common/wm/mru_window_tracker.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm/wm_event.h"
-#include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "ash/shell.h"
+#include "ash/wm/window_util.h"
 #include "base/metrics/user_metrics.h"
 
 namespace ash {
 namespace accelerators {
 
 bool ToggleMinimized() {
-  WmWindow* window = WmShell::Get()->GetActiveWindow();
+  WmWindow* window = WmWindow::Get(wm::GetActiveWindow());
   // Attempt to restore the window that would be cycled through next from
   // the launcher when there is no active window.
   if (!window) {
     MruWindowTracker::WindowList mru_windows(
         Shell::Get()->mru_window_tracker()->BuildMruWindowList());
     if (!mru_windows.empty())
       mru_windows.front()->GetWindowState()->Activate();
     return true;
   }
   wm::WindowState* window_state = window->GetWindowState();
   if (!window_state->CanMinimize())
     return false;
   window_state->Minimize();
   return true;
 }
 
 void ToggleMaximized() {
-  WmWindow* active_window = WmShell::Get()->GetActiveWindow();
+  WmWindow* active_window = WmWindow::Get(wm::GetActiveWindow());
   if (!active_window)
     return;
   base::RecordAction(base::UserMetricsAction("Accel_Toggle_Maximized"));
   wm::WMEvent event(wm::WM_EVENT_TOGGLE_MAXIMIZE);
   active_window->GetWindowState()->OnWMEvent(&event);
 }
 
 void ToggleFullscreen() {
-  WmWindow* active_window = WmShell::Get()->GetActiveWindow();
+  WmWindow* active_window = WmWindow::Get(wm::GetActiveWindow());
   if (!active_window)
     return;
   const wm::WMEvent event(wm::WM_EVENT_TOGGLE_FULLSCREEN);
   active_window->GetWindowState()->OnWMEvent(&event);
 }
 
 }  // namespace accelerators
 }  // namespace ash