ash / wm / tablet_mode / tablet_mode_window_state.cc [blame]

// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ash/wm/tablet_mode/tablet_mode_window_state.h"

#include <utility>

#include "ash/constants/ash_features.h"
#include "ash/drag_drop/tab_drag_drop_delegate.h"
#include "ash/public/cpp/shell_window_ids.h"
#include "ash/public/cpp/window_animation_types.h"
#include "ash/public/cpp/window_properties.h"
#include "ash/screen_util.h"
#include "ash/shell.h"
#include "ash/strings/grit/ash_strings.h"
#include "ash/wm/desks/desks_controller.h"
#include "ash/wm/float/float_controller.h"
#include "ash/wm/mru_window_tracker.h"
#include "ash/wm/overview/overview_controller.h"
#include "ash/wm/screen_pinning_controller.h"
#include "ash/wm/splitview/split_view_utils.h"
#include "ash/wm/tablet_mode/tablet_mode_window_manager.h"
#include "ash/wm/window_positioning_utils.h"
#include "ash/wm/window_properties.h"
#include "ash/wm/window_state_delegate.h"
#include "ash/wm/window_state_util.h"
#include "ash/wm/window_util.h"
#include "ash/wm/wm_event.h"
#include "base/notreached.h"
#include "chromeos/ui/base/window_state_type.h"
#include "chromeos/ui/wm/window_util.h"
#include "ui/aura/client/aura_constants.h"
#include "ui/aura/window.h"
#include "ui/aura/window_delegate.h"
#include "ui/base/mojom/window_show_state.mojom.h"
#include "ui/compositor/layer.h"
#include "ui/wm/core/ime_util_chromeos.h"
#include "ui/wm/core/window_util.h"

namespace ash {
namespace {

using ::chromeos::WindowStateType;

// Sets the restore bounds and show state overrides. These values take
// precedence over the restore bounds and restore show state (if set).
// If |bounds_override| is empty the values are cleared.
void SetWindowRestoreOverrides(
    aura::Window* window,
    const gfx::Rect& bounds_override,
    ui::mojom::WindowShowState window_state_override) {
  if (bounds_override.IsEmpty()) {
    window->ClearProperty(kRestoreWindowStateTypeOverrideKey);
    window->ClearProperty(kRestoreBoundsOverrideKey);
    return;
  }
  window->SetProperty(kRestoreWindowStateTypeOverrideKey,
                      chromeos::ToWindowStateType(window_state_override));
  window->SetProperty(kRestoreBoundsOverrideKey,
                      new gfx::Rect(bounds_override));
}

// Returns the biggest possible size for a window which is about to be
// maximized.
gfx::Size GetMaximumSizeOfWindow(WindowState* window_state) {
  DCHECK(window_state->CanMaximize() || window_state->CanResize());

  gfx::Size workspace_size =
      screen_util::GetMaximizedWindowBoundsInParent(window_state->window())
          .size();

  gfx::Size size =
      window_state->window()->delegate()
          ? window_state->window()->delegate()->GetMaximumSize().value_or(
                gfx::Size())
          : gfx::Size();
  if (size.IsEmpty())
    return workspace_size;

  size.SetToMin(workspace_size);
  return size;
}

// Returns the centered bounds of the given bounds in the work area.
gfx::Rect GetCenteredBounds(const gfx::Rect& bounds_in_parent,
                            WindowState* state_object) {
  gfx::Rect work_area_in_parent =
      screen_util::GetDisplayWorkAreaBoundsInParent(state_object->window());
  work_area_in_parent.ClampToCenteredSize(bounds_in_parent.size());
  return work_area_in_parent;
}

gfx::Rect GetRestoreBounds(WindowState* window_state) {
  if (window_state->IsMinimized() || window_state->IsMaximized() ||
      window_state->IsFullscreen()) {
    gfx::Rect restore_bounds = window_state->GetRestoreBoundsInScreen();
    if (!restore_bounds.IsEmpty())
      return restore_bounds;
  }
  return window_state->window()->GetBoundsInScreen();
}

// True if `window` is floated. If `window` is not floated, it is animated if:
//   - It is the top window in the MRU list.
//   - It the top window in the MRU list is a floated window, and `window` is
//     the second top window in the MRU list.
bool ShouldAnimateWindowForTransition(aura::Window* window) {
  DCHECK(window);

  if (WindowState::Get(window)->IsFloated())
    return true;

  MruWindowTracker::WindowList window_list =
      Shell::Get()->mru_window_tracker()->BuildMruWindowList(kActiveDesk);
  auto* first_mru_window =
      window_list.empty() ? nullptr : window_list.front().get();
  if (first_mru_window && WindowState::Get(first_mru_window)->IsFloated()) {
    auto* second_mru_window =
        window_list.size() < 2u ? nullptr : window_list[1].get();
    return window == second_mru_window;
  }

  return window == first_mru_window;
}

// Returns true if the bounds change of |window| is from VK request and can be
// allowed by the current window's state.
bool BoundsChangeIsFromVKAndAllowed(aura::Window* window) {
  WindowStateType state_type = WindowState::Get(window)->GetStateType();
  if (chromeos::IsNormalWindowStateType(state_type)) {
    return window->GetProperty(wm::kVirtualKeyboardRestoreBoundsKey) != nullptr;
  }

  if (chromeos::IsSnappedWindowStateType(state_type)) {
    return SplitViewController::Get(window)->BoundsChangeIsFromVKAndAllowed(
        window);
  }
  return false;
}

}  // namespace

TabletModeWindowState::TabletModeWindowState(
    aura::Window* window,
    base::WeakPtr<TabletModeWindowManager> creator,
    bool snap,
    bool animate_bounds_on_attach,
    bool entering_tablet_mode)
    : window_(window),
      creator_(creator),
      animate_bounds_on_attach_(animate_bounds_on_attach) {
  WindowState* state = WindowState::Get(window);
  current_state_type_ = state->GetStateType();
  DCHECK(!snap || SplitViewController::Get(Shell::GetPrimaryRootWindow())
                      ->CanKeepCurrentSnapRatio(window));

  // Snapped and floated windows maintain their state; other windows become
  // maximized if possible, centered with a backdrop if not possible.
  state_type_on_attach_ = snap || state->IsFloated()
                              ? current_state_type_
                              : state->GetWindowTypeOnMaximizable();
  WindowState::ScopedBoundsChangeAnimation bounds_animation(
      window, entering_tablet_mode && !ShouldAnimateWindowForTransition(window)
                  ? WindowState::BoundsChangeAnimationType::kAnimateZero
                  : WindowState::BoundsChangeAnimationType::kAnimate);
  old_window_bounds_in_screen_ = window->GetBoundsInScreen();
  old_state_.reset(
      state->SetStateObject(std::unique_ptr<State>(this)).release());
}

TabletModeWindowState::~TabletModeWindowState() {
  if (creator_) {
    creator_->WindowStateDestroyed(window_);
  }
}

// static
void TabletModeWindowState::UpdateWindowPosition(
    WindowState* window_state,
    WindowState::BoundsChangeAnimationType animation_type) {
  const gfx::Rect bounds_in_parent = GetBoundsInTabletMode(window_state);
  if (bounds_in_parent == window_state->window()->GetTargetBounds())
    return;

  switch (animation_type) {
    case WindowState::BoundsChangeAnimationType::kNone:
      window_state->SetBoundsDirect(bounds_in_parent);
      break;
    case WindowState::BoundsChangeAnimationType::kCrossFade:
      window_state->SetBoundsDirectCrossFade(bounds_in_parent);
      break;
    case WindowState::BoundsChangeAnimationType::kAnimate:
      window_state->SetBoundsDirectAnimated(bounds_in_parent);
      break;
    case WindowState::BoundsChangeAnimationType::kCrossFadeFloat:
      window_state->SetBoundsDirectCrossFade(bounds_in_parent,
                                             /*float_state=*/true);
      break;
    case WindowState::BoundsChangeAnimationType::kCrossFadeUnfloat:
      window_state->SetBoundsDirectCrossFade(bounds_in_parent,
                                             /*float_state=*/false);
      break;
    case WindowState::BoundsChangeAnimationType::kAnimateZero:
      NOTREACHED();
  }
}

// static
gfx::Rect TabletModeWindowState::GetBoundsInTabletMode(
    WindowState* state_object) {
  aura::Window* window = state_object->window();

  if (state_object->IsFullscreen() || state_object->IsPinned())
    return screen_util::GetFullscreenWindowBoundsInParent(window);

  if (state_object->GetStateType() == WindowStateType::kPrimarySnapped) {
    return SplitViewController::Get(Shell::GetPrimaryRootWindow())
        ->GetSnappedWindowBoundsInParent(
            SnapPosition::kPrimary, window,
            state_object->snap_ratio().value_or(chromeos::kDefaultSnapRatio));
  }

  if (state_object->GetStateType() == WindowStateType::kSecondarySnapped) {
    return SplitViewController::Get(Shell::GetPrimaryRootWindow())
        ->GetSnappedWindowBoundsInParent(
            SnapPosition::kSecondary, window,
            state_object->snap_ratio().value_or(chromeos::kDefaultSnapRatio));
  }

  if (state_object->IsFloated()) {
    return FloatController::GetFloatWindowTabletBounds(window);
  }

  gfx::Rect bounds_in_parent;
  // Make the window as big as possible.

  // Do no maximize the transient children, which should be stacked
  // above the transient parent.
  if ((state_object->CanMaximize() || state_object->CanResize()) &&
      ::wm::GetTransientParent(state_object->window()) == nullptr) {
    bounds_in_parent.set_size(GetMaximumSizeOfWindow(state_object));
  } else {
    // We prefer the user given window dimensions over the current windows
    // dimensions since they are likely to be the result from some other state
    // object logic.
    if (state_object->HasRestoreBounds())
      bounds_in_parent = state_object->GetRestoreBoundsInParent();
    else
      bounds_in_parent = state_object->window()->bounds();
  }
  return GetCenteredBounds(bounds_in_parent, state_object);
}

void TabletModeWindowState::LeaveTabletMode(WindowState* window_state,
                                            bool was_in_overview) {
  // Only do bounds change animation if the window was showing in overview,
  // or the top window or a window showing in splitview before leaving tablet
  // mode, and the window has changed its state. Otherwise, restore its bounds
  // immediately.
  WindowState::BoundsChangeAnimationType animation_type =
      was_in_overview || window_state->IsSnapped() ||
              ShouldAnimateWindowForTransition(window_state->window())
          ? WindowState::BoundsChangeAnimationType::kAnimate
          : WindowState::BoundsChangeAnimationType::kNone;
  if (old_state_->GetType() == window_state->GetStateType() &&
      !window_state->IsNormalStateType() && !window_state->IsFloated()) {
    animation_type = WindowState::BoundsChangeAnimationType::kNone;
  }

  // Note: When we return we will destroy ourselves with the |our_reference|.
  WindowState::ScopedBoundsChangeAnimation bounds_animation(
      window_state->window(), animation_type);
  std::unique_ptr<WindowState::State> our_reference =
      window_state->SetStateObject(std::move(old_state_));
}

void TabletModeWindowState::OnWMEvent(WindowState* window_state,
                                      const WMEvent* event) {
  // Ignore events that are sent during the exit transition.
  if (ignore_wm_events_) {
    return;
  }

  const chromeos::WindowStateType previous_state_type =
      window_state->GetStateType();

  switch (event->type()) {
    case WM_EVENT_TOGGLE_FULLSCREEN:
      ToggleFullScreen(window_state, window_state->delegate());
      break;
    case WM_EVENT_FULLSCREEN:
      UpdateWindow(window_state, WindowStateType::kFullscreen,
                   /*animate=*/true);
      break;
    case WM_EVENT_PIN:
      if (!Shell::Get()->screen_pinning_controller()->IsPinned()) {
        UpdateWindow(window_state, WindowStateType::kPinned,
                     /*animate=*/true);
      }
      break;
    case WM_EVENT_PIP:
      // PIP windows are not managed by TabletModeWindowManager even if the
      // window is in tablet mode. PIP window uses DefaultState instead, not
      // TabletModeWindowState.
      NOTREACHED();
    case WM_EVENT_TRUSTED_PIN:
      if (!Shell::Get()->screen_pinning_controller()->IsPinned()) {
        UpdateWindow(window_state, WindowStateType::kTrustedPinned,
                     /*animate=*/true);
      }
      break;
    case WM_EVENT_TOGGLE_MAXIMIZE_CAPTION:
    case WM_EVENT_TOGGLE_VERTICAL_MAXIMIZE:
    case WM_EVENT_TOGGLE_HORIZONTAL_MAXIMIZE:
    case WM_EVENT_TOGGLE_MAXIMIZE:
    case WM_EVENT_MAXIMIZE:
      UpdateWindow(window_state, window_state->GetWindowTypeOnMaximizable(),
                   /*animate=*/true);
      break;
    case WM_EVENT_NORMAL: {
      // `WM_EVENT_NORMAL` may be restoring state from minimized.
      if (window_state->window()->GetProperty(aura::client::kIsRestoringKey)) {
        DoRestore(window_state);
      } else {
        UpdateWindow(window_state, window_state->GetWindowTypeOnMaximizable(),
                     /*animate=*/true);
      }
      break;
    }
    case WM_EVENT_RESTORE: {
      // We special handle `WM_EVENT_RESTORE` event here.
      DoRestore(window_state);
      break;
    }
    case WM_EVENT_FLOAT:
      // Not all windows can be floated.
      if (!chromeos::wm::CanFloatWindow(window_state->window()))
        break;

      UpdateWindow(window_state, WindowStateType::kFloated,
                   /*=animate=*/true);
      break;
    case WM_EVENT_SNAP_PRIMARY:
    case WM_EVENT_SNAP_SECONDARY:
      CHECK(event->AsSnapEvent());
      DoTabletSnap(window_state, event->type(),
                   event->AsSnapEvent()->snap_ratio(),
                   event->AsSnapEvent()->snap_action_source());
      break;
    case WM_EVENT_CYCLE_SNAP_PRIMARY:
      CycleTabletSnap(window_state, SnapPosition::kPrimary);
      break;
    case WM_EVENT_CYCLE_SNAP_SECONDARY:
      CycleTabletSnap(window_state, SnapPosition::kSecondary);
      break;
    case WM_EVENT_MINIMIZE:
      UpdateWindow(window_state, WindowStateType::kMinimized,
                   /*=animate=*/true);
      break;
    case WM_EVENT_SHOW_INACTIVE:
      break;
    case WM_EVENT_SET_BOUNDS: {
      gfx::Rect bounds_in_parent =
          event->AsSetBoundsWMEvent()->requested_bounds_in_parent();
      if (bounds_in_parent.IsEmpty())
        break;

      if (window_state->is_dragged() ||
          TabDragDropDelegate::IsSourceWindowForDrag(window_state->window()) ||
          BoundsChangeIsFromVKAndAllowed(window_state->window())) {
        // If the window is the current tab-dragged window or the current tab-
        // dragged window's source window, we may need to update its bounds
        // during dragging.
        window_state->SetBoundsDirect(bounds_in_parent);
      } else if (current_state_type_ == WindowStateType::kMaximized) {
        // Having a maximized window, it could have been created with an empty
        // size and the caller should get his size upon leaving the maximized
        // mode. As such we set the restore bounds to the requested bounds.
        window_state->SetRestoreBoundsInParent(bounds_in_parent);
      } else if (current_state_type_ != WindowStateType::kMinimized &&
                 current_state_type_ != WindowStateType::kFullscreen &&
                 current_state_type_ != WindowStateType::kPinned &&
                 current_state_type_ != WindowStateType::kTrustedPinned &&
                 current_state_type_ != WindowStateType::kPrimarySnapped &&
                 current_state_type_ != WindowStateType::kSecondarySnapped &&
                 current_state_type_ != WindowStateType::kFloated) {
        // In all other cases (except for minimized windows) we respect the
        // requested bounds and center it to a fully visible area on the screen.
        bounds_in_parent = GetCenteredBounds(bounds_in_parent, window_state);
        if (bounds_in_parent != window_state->window()->bounds()) {
          if (window_state->window()->IsVisible() &&
              event->AsSetBoundsWMEvent()->animate()) {
            window_state->SetBoundsDirectAnimated(bounds_in_parent);
          } else {
            window_state->SetBoundsDirect(bounds_in_parent);
          }
        }
      }
      break;
    }
    case WM_EVENT_ADDED_TO_WORKSPACE:
      // Update the window to maximized or centered if it cannot maximize.
      // If an already snapped window or floated or pinned window gets added to
      // the workspace, the window should not be forced maximized, rather retain
      // its previous state.
      UpdateWindow(window_state,
                   AdjustStateForTabletMode(window_state, current_state_type_),
                   /*animate=*/true);
      break;
    case WM_EVENT_DISPLAY_METRICS_CHANGED:
      if (current_state_type_ == WindowStateType::kMinimized) {
        break;
      }
      const DisplayMetricsChangedWMEvent* display_event =
          event->AsDisplayMetricsChangedWMEvent();
      const bool display_bounds_changed =
          display_event->display_bounds_changed();
      const bool work_area_changed = display_event->work_area_changed();
      if (display_bounds_changed || work_area_changed) {
        // Don't animate on a screen rotation - just snap to new size.
        UpdateBounds(window_state, previous_state_type,
                     /*animate=*/work_area_changed);
      }
      break;
  }
}

WindowStateType TabletModeWindowState::GetType() const {
  return current_state_type_;
}

void TabletModeWindowState::AttachState(WindowState* window_state,
                                        WindowState::State* previous_state) {
  current_state_type_ = previous_state->GetType();

  gfx::Rect restore_bounds = GetRestoreBounds(window_state);
  if (!restore_bounds.IsEmpty()) {
    // We do not want to do a session restore to our window states. Therefore
    // we tell the window to use the current default states instead.
    SetWindowRestoreOverrides(window_state->window(), restore_bounds,
                              window_state->GetShowState());
  }

  if (current_state_type_ != WindowStateType::kMaximized &&
      current_state_type_ != WindowStateType::kMinimized &&
      current_state_type_ != WindowStateType::kFullscreen &&
      // Skip updating float here as the minimum size of the window may not be
      // updated at this point and float tablet bounds depend on minimum size.
      // It will get updated later in `FloatController::OnTabletModeStarted`.
      current_state_type_ != WindowStateType::kFloated &&
      current_state_type_ != WindowStateType::kPinned &&
      current_state_type_ != WindowStateType::kTrustedPinned) {
    UpdateWindow(window_state, state_type_on_attach_,
                 animate_bounds_on_attach_);
  }
}

void TabletModeWindowState::DetachState(WindowState* window_state) {
  // From now on, we can use the default session restore mechanism again.
  SetWindowRestoreOverrides(window_state->window(), gfx::Rect(),
                            ui::mojom::WindowShowState::kNormal);
}

void TabletModeWindowState::UpdateWindow(WindowState* window_state,
                                         WindowStateType target_state,
                                         bool animated) {
  aura::Window* window = window_state->window();

  DCHECK(target_state == WindowStateType::kMinimized ||
         target_state == WindowStateType::kMaximized ||
         target_state == WindowStateType::kPinned ||
         target_state == WindowStateType::kTrustedPinned ||
         (target_state == WindowStateType::kNormal &&
          (!window_state->CanMaximize() || !!wm::GetTransientParent(window))) ||
         target_state == WindowStateType::kFullscreen ||
         target_state == WindowStateType::kPrimarySnapped ||
         target_state == WindowStateType::kSecondarySnapped ||
         target_state == WindowStateType::kFloated);

  if (current_state_type_ == target_state) {
    if (target_state == WindowStateType::kMinimized)
      return;
    // If the state type did not change, update it accordingly.
    UpdateBounds(window_state, current_state_type_, animated);
    return;
  }

  const WindowStateType old_state_type = current_state_type_;
  current_state_type_ = target_state;
  window_state->UpdateWindowPropertiesFromStateType();
  window_state->NotifyPreStateTypeChange(old_state_type);

  if (target_state == WindowStateType::kFloated)
    Shell::Get()->float_controller()->FloatForTablet(window, old_state_type);

  // Unfloat floated window when exiting float state to another state.
  if (old_state_type == WindowStateType::kFloated)
    Shell::Get()->float_controller()->UnfloatImpl(window);

  if (target_state == WindowStateType::kMinimized) {
    wm::SetWindowVisibilityAnimationType(
        window, WINDOW_VISIBILITY_ANIMATION_TYPE_MINIMIZE);
    window->Hide();
    if (window_state->IsActive())
      window_state->Deactivate();
  } else {
    UpdateBounds(window_state, old_state_type, animated);
  }

  if ((window->layer()->GetTargetVisibility() ||
       old_state_type == WindowStateType::kMinimized) &&
      !window->layer()->visible()) {
    // The layer may be hidden if the window was previously minimized. Make
    // sure it's visible.
    window->Show();
  }

  window_state->NotifyPostStateTypeChange(old_state_type);

  if (chromeos::IsPinnedWindowStateType(old_state_type) ||
      chromeos::IsPinnedWindowStateType(target_state)) {
    Shell::Get()->screen_pinning_controller()->SetPinnedWindow(window);
    if (window_state->delegate()) {
      window_state->delegate()->ToggleLockedFullscreen(window_state);
    }
  }
}

WindowStateType TabletModeWindowState::AdjustStateForTabletMode(
    WindowState* window_state,
    WindowStateType current_state_type) {
  if (chromeos::IsSnappedWindowStateType(current_state_type) ||
      chromeos::IsPinnedWindowStateType(current_state_type) ||
      current_state_type == chromeos::WindowStateType::kFloated) {
    return window_state->GetStateType();
  }

  return window_state->GetWindowTypeOnMaximizable();
}

void TabletModeWindowState::UpdateBounds(
    WindowState* window_state,
    chromeos::WindowStateType previous_state,
    bool animated) {
  // Do not update minimized windows bounds until it was unminimized.
  if (current_state_type_ == WindowStateType::kMinimized)
    return;

  gfx::Rect bounds_in_parent = GetBoundsInTabletMode(window_state);
  // If we have a target bounds rectangle, we center it and set it
  // accordingly.
  if (!bounds_in_parent.IsEmpty() &&
      bounds_in_parent != window_state->window()->bounds()) {
    if (!window_state->window()->IsVisible() || !animated) {
      window_state->SetBoundsDirect(bounds_in_parent);
    } else {
      if (window_state->bounds_animation_type() ==
          WindowState::BoundsChangeAnimationType::kAnimateZero) {
        // Just use the normal bounds animation with ZERO tween with long enough
        // duration for STEP_END. The animation will be stopped when the to
        // window's animation ends.
        window_state->SetBoundsDirectAnimated(
            bounds_in_parent, base::Seconds(1), gfx::Tween::ZERO);
        return;
      }

      // Use a custom cross fade for floating or unfloating. Do not use cross
      // fade if the state hasn't changed.
      const bool previous_floated = previous_state == WindowStateType::kFloated;
      const bool current_floated = window_state->IsFloated();
      if (previous_floated ^ current_floated) {
        window_state->SetBoundsDirectCrossFade(bounds_in_parent,
                                               /*float_state=*/current_floated);
        return;
      }

      // Use cross fade in some cases to avoid flashing and/or for better
      // performance.
      if (window_state->IsMaximized()) {
        window_state->SetBoundsDirectCrossFade(bounds_in_parent);
      } else {
        window_state->SetBoundsDirectAnimated(bounds_in_parent);
      }
    }
  }
}

void TabletModeWindowState::CycleTabletSnap(WindowState* window_state,
                                            SnapPosition snap_position) {
  aura::Window* window = window_state->window();
  SplitViewController* split_view_controller = SplitViewController::Get(window);
  // If |window| is already snapped in |snap_position|, then unsnap |window|.
  if (window == split_view_controller->GetSnappedWindow(snap_position)) {
    UpdateWindow(window_state, window_state->GetWindowTypeOnMaximizable(),
                 /*animate=*/true);
    window_state->ReadOutWindowCycleSnapAction(
        IDS_WM_RESTORE_SNAPPED_WINDOW_ON_SHORTCUT);
    return;
  }
  // If |window| can snap in split view, then snap |window| in |snap_position|.
  if (split_view_controller->CanSnapWindow(window,
                                           chromeos::kDefaultSnapRatio)) {
    split_view_controller->SnapWindow(
        window, snap_position, WindowSnapActionSource::kKeyboardShortcutToSnap);
    window_state->ReadOutWindowCycleSnapAction(
        snap_position == SnapPosition::kPrimary
            ? IDS_WM_SNAP_WINDOW_TO_LEFT_ON_SHORTCUT
            : IDS_WM_SNAP_WINDOW_TO_RIGHT_ON_SHORTCUT);
    return;
  }
  // Otherwise, show the cannot snap toast.
  ShowAppCannotSnapToast();
}

void TabletModeWindowState::DoTabletSnap(
    WindowState* window_state,
    WMEventType snap_event_type,
    float snap_ratio,
    WindowSnapActionSource snap_action_source) {
  DCHECK(snap_event_type == WM_EVENT_SNAP_PRIMARY ||
         snap_event_type == WM_EVENT_SNAP_SECONDARY);

  aura::Window* window = window_state->window();
  SplitViewController* split_view_controller = SplitViewController::Get(window);
  if (!split_view_controller->CanSnapWindow(window, snap_ratio)) {
    ShowAppCannotSnapToast();
    return;
  }

  window_state->SetBoundsChangedByUser(true);
  chromeos::WindowStateType new_state_type =
      snap_event_type == WM_EVENT_SNAP_PRIMARY
          ? WindowStateType::kPrimarySnapped
          : WindowStateType::kSecondarySnapped;
  window_state->RecordWindowSnapActionSource(snap_action_source);

  // A snap WMEvent will put the window in tablet split view.
  split_view_controller->OnSnapEvent(window, snap_event_type,
                                     snap_action_source);

  // Change window state and bounds to the snapped window state and bounds.
  UpdateWindow(window_state, new_state_type, /*animate=*/false);
}

void TabletModeWindowState::DoRestore(WindowState* window_state) {
  WindowStateType restore_state = window_state->GetRestoreWindowState();
  if (chromeos::IsSnappedWindowStateType(restore_state)) {
    DoTabletSnap(window_state,
                 restore_state == WindowStateType::kPrimarySnapped
                     ? WM_EVENT_SNAP_PRIMARY
                     : WM_EVENT_SNAP_SECONDARY,
                 chromeos::kDefaultSnapRatio,
                 WindowSnapActionSource::kSnapByWindowStateRestore);
    return;
  }

  UpdateWindow(window_state, restore_state, /*animate=*/true);
}

}  // namespace ash