Makes ScreenPinningController clear map after removing observers

ash/common/wm/workspace/workspace_layout_manager.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/common/wm/workspace/workspace_layout_manager.h"
 
 #include <algorithm>
 
 #include "ash/common/keyboard/keyboard_observer_register.h"
 #include "ash/common/session/session_controller.h"
@@ skipping 302 matching lines @@
     // always-on-top state change, because it is kept disabled regardless of
     // the fullscreen state change.
     return;
   }
 
   UpdateAlwaysOnTop(is_fullscreen_ ? wm::GetWindowForFullscreenMode(window_)
                                    : nullptr);
 }
 
 void WorkspaceLayoutManager::OnPinnedStateChanged(WmWindow* pinned_window) {
-  if (!WmShell::Get()->IsPinned() && is_fullscreen_) {
+  const bool is_pinned = WmShell::Get()->IsPinned();
+  if (!is_pinned && is_fullscreen_) {
     // On exiting from pinned mode, if the workspace is still in fullscreen
     // mode, then this event does not trigger the restoring yet. On exiting
     // from fullscreen, the temporarily disabled always-on-top property will be
     // restored.
     return;
   }
 
-  UpdateAlwaysOnTop(WmShell::Get()->IsPinned() ? pinned_window : nullptr);
+  UpdateAlwaysOnTop(is_pinned ? pinned_window : nullptr);
 }
 
 void WorkspaceLayoutManager::OnVirtualKeyboardStateChanged(
     bool activated,
     WmWindow* root_window) {
   UpdateKeyboardObserverFromStateChanged(activated, root_window, root_window_,
                                          &keyboard_observer_);
 }
 
 //////////////////////////////////////////////////////////////////////////////
@@ skipping 52 matching lines @@
   for (auto* window : windows) {
     wm::WindowState* window_state = window->GetWindowState();
     if (window_on_top)
       window_state->DisableAlwaysOnTop(window_on_top);
     else
       window_state->RestoreAlwaysOnTop();
   }
 }
 
 }  // namespace ash