[Docking] Persists docked state on Chrome OS

ash/wm/dock/docked_window_resizer.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/wm/dock/docked_window_resizer.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf.h"
@@ skipping 281 matching lines @@
       aura::Window* previous_parent = window->parent();
       aura::client::ParentWindowWithContext(window, window, near_last_location);
       if (window->parent() != previous_parent) {
         wm::ReparentTransientChildrenOfChild(window,
                                              previous_parent,
                                              window->parent());
       }
       action = was_docked_ ? DOCKED_ACTION_UNDOCK : DOCKED_ACTION_NONE;
     }
   } else {
-    // Docked state was not changed but still need to record a UMA action.
+    // |action| is recorded in UMA and used to maintain |window_state_|.
     if (is_resized && is_docked_ && was_docked_)
       action = DOCKED_ACTION_RESIZE;
     else if (is_docked_ && was_docked_)
       action = DOCKED_ACTION_REORDER;
     else if (is_docked_ && !was_docked_)
       action = DOCKED_ACTION_DOCK;
+    else if (!is_docked_ && was_docked_)
+      action = DOCKED_ACTION_UNDOCK;
     else
       action = DOCKED_ACTION_NONE;
   }
   // When a window is newly docked it is auto-sized by docked layout adjusting
   // to other windows. If it is just dragged (but not resized) while being
   // docked it is auto-sized unless it has been resized while being docked
   // before.
   if (is_docked_) {
     wm::GetWindowState(window)->set_bounds_changed_by_user(
         was_docked_ && (is_resized || was_bounds_changed_by_user_));
   }
 
   if (action == DOCKED_ACTION_DOCK) {
     const wm::WMEvent event(wm::WM_EVENT_DOCK);
     window_state_->OnWMEvent(&event);
   } else if (wm::GetWindowState(window)->IsDocked() &&
              action == DOCKED_ACTION_UNDOCK) {
     const wm::WMEvent event(wm::WM_EVENT_NORMAL);
     window_state_->OnWMEvent(&event);
   }
 
   return action;
 }
 
 }  // namespace ash