chromeos: Move files in //ash/common to //ash, part 2

ash/common/wm/fullscreen_window_finder.cc

-// 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/common/wm/fullscreen_window_finder.h"
-
-#include "ash/common/wm/switchable_windows.h"
-#include "ash/common/wm/window_state.h"
-#include "ash/common/wm_shell.h"
-#include "ash/common/wm_window.h"
-#include "ash/public/cpp/shell_window_ids.h"
-#include "ui/compositor/layer.h"
-
-namespace ash {
-namespace wm {
-
-WmWindow* GetWindowForFullscreenMode(WmWindow* context) {
-  WmWindow* topmost_window = nullptr;
-  WmWindow* active_window = context->GetShell()->GetActiveWindow();
-  if (active_window &&
-      active_window->GetRootWindow() == context->GetRootWindow() &&
-      IsSwitchableContainer(active_window->GetParent())) {
-    // Use the active window when it is on the current root window to determine
-    // the fullscreen state to allow temporarily using a panel or docked window
-    // (which are always above the default container) while a fullscreen
-    // window is open. We only use the active window when in a switchable
-    // container as the launcher should not exit fullscreen mode.
-    topmost_window = active_window;
-  } else {
-    // Otherwise, use the topmost window on the root window's default container
-    // when there is no active window on this root window.
-    std::vector<WmWindow*> windows =
-        context->GetRootWindow()
-            ->GetChildByShellWindowId(kShellWindowId_DefaultContainer)
-            ->GetChildren();
-    for (auto iter = windows.rbegin(); iter != windows.rend(); ++iter) {
-      if ((*iter)->GetWindowState()->IsUserPositionable() &&
-          (*iter)->GetLayerTargetVisibility()) {
-        topmost_window = *iter;
-        break;
-      }
-    }
-  }
-  while (topmost_window) {
-    if (topmost_window->GetWindowState()->IsFullscreen())
-      return topmost_window;
-    topmost_window = topmost_window->GetTransientParent();
-  }
-  return nullptr;
-}
-
-}  // namespace wm
-}  // namespace ash