Refactor backdrop that is currently used in the maximized mode.

ash/wm/maximize_mode/workspace_backdrop_delegate.cc

-// Copyright 2014 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/maximize_mode/workspace_backdrop_delegate.h"
-
-#include "ash/public/cpp/shell_window_ids.h"
-#include "ash/root_window_controller.h"
-#include "ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h"
-#include "ash/wm_window.h"
-#include "base/auto_reset.h"
-#include "ui/compositor/layer.h"
-#include "ui/compositor/scoped_layer_animation_settings.h"
-#include "ui/views/background.h"
-#include "ui/views/widget/widget.h"
-#include "ui/wm/core/window_animations.h"
-#include "ui/wm/core/window_util.h"
-
-namespace ash {
-namespace {
-
-// The opacity of the backdrop.
-const float kBackdropOpacity = 1.0f;
-
-}  // namespace
-
-WorkspaceBackdropDelegate::WorkspaceBackdropDelegate(WmWindow* container)
-    : container_(container), in_restacking_(false) {
-  background_ = new views::Widget;
-  views::Widget::InitParams params(
-      views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
-  params.bounds = container_->GetBoundsInScreen();
-  params.layer_type = ui::LAYER_SOLID_COLOR;
-  params.name = "WorkspaceBackdropDelegate";
-  // To disallow the MRU list from picking this window up it should not be
-  // activateable.
-  params.activatable = views::Widget::InitParams::ACTIVATABLE_NO;
-  DCHECK_NE(kShellWindowId_Invalid, container_->aura_window()->id());
-  container_->GetRootWindowController()->ConfigureWidgetInitParamsForContainer(
-      background_, container_->aura_window()->id(), &params);
-  background_->Init(params);
-  background_window_ = WmWindow::Get(background_->GetNativeWindow());
-  // Do not use the animation system. We don't want the bounds animation and
-  // opacity needs to get set to |kBackdropOpacity|.
-  background_window_->SetVisibilityAnimationTransition(::wm::ANIMATE_NONE);
-  background_window_->GetLayer()->SetColor(SK_ColorBLACK);
-  // Make sure that the layer covers visibly everything - including the shelf.
-  background_window_->GetLayer()->SetBounds(params.bounds);
-  DCHECK(background_window_->GetBounds() == params.bounds);
-  Show();
-  RestackBackdrop();
-}
-
-WorkspaceBackdropDelegate::~WorkspaceBackdropDelegate() {
-  // TODO: animations won't work right with mus: http://crbug.com/548396.
-  ::wm::ScopedHidingAnimationSettings hiding_settings(
-      background_->GetNativeView());
-  background_->Close();
-  background_window_->GetLayer()->SetOpacity(0.0f);
-}
-
-void WorkspaceBackdropDelegate::OnWindowAddedToLayout(WmWindow* child) {
-  RestackBackdrop();
-}
-
-void WorkspaceBackdropDelegate::OnWindowRemovedFromLayout(WmWindow* child) {
-  RestackBackdrop();
-}
-
-void WorkspaceBackdropDelegate::OnChildWindowVisibilityChanged(WmWindow* child,
-                                                               bool visible) {
-  RestackBackdrop();
-}
-
-void WorkspaceBackdropDelegate::OnWindowStackingChanged(WmWindow* window) {
-  RestackBackdrop();
-}
-
-void WorkspaceBackdropDelegate::OnPostWindowStateTypeChange(
-    wm::WindowState* window_state,
-    wm::WindowStateType old_type) {
-  RestackBackdrop();
-}
-
-void WorkspaceBackdropDelegate::RestackBackdrop() {
-  // Avoid recursive calls.
-  if (in_restacking_)
-    return;
-
-  WmWindow* window = GetCurrentTopWindow();
-  if (!window) {
-    // Hide backdrop since no suitable window was found.
-    background_->Hide();
-    return;
-  }
-  if (window == background_window_ && background_->IsVisible())
-    return;
-  if (window->GetRootWindow() != background_window_->GetRootWindow())
-    return;
-  // We are changing the order of windows which will cause recursion.
-  base::AutoReset<bool> lock(&in_restacking_, true);
-  if (!background_->IsVisible())
-    Show();
-  // Since the backdrop needs to be immediately behind the window and the
-  // stacking functions only guarantee a "it's above or below", we need
-  // to re-arrange the two windows twice.
-  container_->StackChildAbove(background_window_, window);
-  container_->StackChildAbove(window, background_window_);
-}
-
-WmWindow* WorkspaceBackdropDelegate::GetCurrentTopWindow() {
-  const WmWindow::Windows windows = container_->GetChildren();
-  for (auto window_iter = windows.rbegin(); window_iter != windows.rend();
-       ++window_iter) {
-    WmWindow* window = *window_iter;
-    if (window->GetTargetVisibility() &&
-        window->GetType() == ui::wm::WINDOW_TYPE_NORMAL &&
-        window->CanActivate())
-      return window;
-  }
-  return nullptr;
-}
-
-void WorkspaceBackdropDelegate::Show() {
-  background_window_->GetLayer()->SetOpacity(0.0f);
-  background_->Show();
-  background_->SetFullscreen(true);
-  ui::ScopedLayerAnimationSettings settings(
-      background_window_->GetLayer()->GetAnimator());
-  background_window_->GetLayer()->SetOpacity(kBackdropOpacity);
-}
-
-}  // namespace ash