src/ash/wm/toplevel_window_event_handler.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ash/wm/toplevel_window_event_handler.h"
   6
   7 #include "ash/shell.h"
   8 #include "ash/wm/resize_shadow_controller.h"
   9 #include "ash/wm/window_resizer.h"
  10 #include "ash/wm/window_state.h"
  11 #include "ash/wm/window_state_observer.h"
  12 #include "ash/wm/window_util.h"
  13 #include "ash/wm/workspace/snap_sizer.h"
  14 #include "base/message_loop/message_loop.h"
  15 #include "base/run_loop.h"
  16 #include "ui/aura/client/cursor_client.h"
  17 #include "ui/aura/env.h"
  18 #include "ui/aura/root_window.h"
  19 #include "ui/aura/window.h"
  20 #include "ui/aura/window_delegate.h"
  21 #include "ui/aura/window_observer.h"
  22 #include "ui/base/cursor/cursor.h"
  23 #include "ui/base/hit_test.h"
  24 #include "ui/base/ui_base_types.h"
  25 #include "ui/events/event.h"
  26 #include "ui/events/event_utils.h"
  27 #include "ui/events/gestures/gesture_recognizer.h"
  28 #include "ui/gfx/geometry/point_conversions.h"
  29 #include "ui/gfx/screen.h"
  30
  31 namespace {
  32 const double kMinHorizVelocityForWindowSwipe = 1100;
  33 const double kMinVertVelocityForWindowMinimize = 1000;
  34 }
  35
  36 namespace ash {
  37
  38 namespace {
  39
  40 // Returns whether |window| can be moved via a two finger drag given
  41 // the hittest results of the two fingers.
  42 bool CanStartTwoFingerMove(aura::Window* window,
  43                            int window_component1,
  44                            int window_component2) {
  45   // We allow moving a window via two fingers when the hittest components are
  46   // HTCLIENT. This is done so that a window can be dragged via two fingers when
  47   // the tab strip is full and hitting the caption area is difficult. We check
  48   // the window type and the show state so that we do not steal touches from the
  49   // web contents.
  50   if (!ash::wm::GetWindowState(window)->IsNormalShowState() ||
  51       window->type() != ui::wm::WINDOW_TYPE_NORMAL) {
  52     return false;
  53   }
  54   int component1_behavior =
  55       WindowResizer::GetBoundsChangeForWindowComponent(window_component1);
  56   int component2_behavior =
  57       WindowResizer::GetBoundsChangeForWindowComponent(window_component2);
  58   return (component1_behavior & WindowResizer::kBoundsChange_Resizes) == 0 &&
  59       (component2_behavior & WindowResizer::kBoundsChange_Resizes) == 0;
  60 }
  61
  62 // Returns whether |window| can be moved or resized via one finger given
  63 // |window_component|.
  64 bool CanStartOneFingerDrag(int window_component) {
  65   return WindowResizer::GetBoundsChangeForWindowComponent(
  66       window_component) != 0;
  67 }
  68
  69 gfx::Point ConvertPointToParent(aura::Window* window,
  70                                 const gfx::Point& point) {
  71   gfx::Point result(point);
  72   aura::Window::ConvertPointToTarget(window, window->parent(), &result);
  73   return result;
  74 }
  75
  76 // Returns the window component containing |event|'s location.
  77 int GetWindowComponent(aura::Window* window, const ui::LocatedEvent& event) {
  78   return window->delegate()->GetNonClientComponent(event.location());
  79 }
  80
  81 }  // namespace
  82
  83 // ScopedWindowResizer ---------------------------------------------------------
  84
  85 // Wraps a WindowResizer and installs an observer on its target window.  When
  86 // the window is destroyed ResizerWindowDestroyed() is invoked back on the
  87 // ToplevelWindowEventHandler to clean up.
  88 class ToplevelWindowEventHandler::ScopedWindowResizer
  89     : public aura::WindowObserver,
  90       public wm::WindowStateObserver {
  91  public:
  92   ScopedWindowResizer(ToplevelWindowEventHandler* handler,
  93                       WindowResizer* resizer);
  94   virtual ~ScopedWindowResizer();
  95
  96   // Returns true if the drag moves the window and does not resize.
  97   bool IsMove() const;
  98
  99   WindowResizer* resizer() { return resizer_.get(); }
 100
 101   // WindowObserver overrides:
 102   virtual void OnWindowHierarchyChanging(
 103       const HierarchyChangeParams& params) OVERRIDE;
 104   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
 105
 106   // WindowStateObserver overrides:
 107   virtual void OnWindowShowTypeChanged(wm::WindowState* window_state,
 108                                        wm::WindowShowType type) OVERRIDE;
 109
 110  private:
 111   ToplevelWindowEventHandler* handler_;
 112   scoped_ptr<WindowResizer> resizer_;
 113
 114   DISALLOW_COPY_AND_ASSIGN(ScopedWindowResizer);
 115 };
 116
 117 ToplevelWindowEventHandler::ScopedWindowResizer::ScopedWindowResizer(
 118     ToplevelWindowEventHandler* handler,
 119     WindowResizer* resizer)
 120     : handler_(handler),
 121       resizer_(resizer) {
 122   resizer_->GetTarget()->AddObserver(this);
 123   wm::GetWindowState(resizer_->GetTarget())->AddObserver(this);
 124 }
 125
 126 ToplevelWindowEventHandler::ScopedWindowResizer::~ScopedWindowResizer() {
 127   resizer_->GetTarget()->RemoveObserver(this);
 128   wm::GetWindowState(resizer_->GetTarget())->RemoveObserver(this);
 129 }
 130
 131 bool ToplevelWindowEventHandler::ScopedWindowResizer::IsMove() const {
 132   return resizer_->details().bounds_change ==
 133       WindowResizer::kBoundsChange_Repositions;
 134 }
 135
 136 void ToplevelWindowEventHandler::ScopedWindowResizer::OnWindowHierarchyChanging(
 137     const HierarchyChangeParams& params) {
 138   if (params.receiver != resizer_->GetTarget())
 139     return;
 140   wm::WindowState* state = wm::GetWindowState(params.receiver);
 141   if (state->continue_drag_after_reparent())
 142     state->set_continue_drag_after_reparent(false);
 143   else
 144     handler_->CompleteDrag(DRAG_COMPLETE);
 145 }
 146
 147 void ToplevelWindowEventHandler::ScopedWindowResizer::OnWindowShowTypeChanged(
 148     wm::WindowState* window_state,
 149     wm::WindowShowType old) {
 150   if (!window_state->IsNormalShowState())
 151     handler_->CompleteDrag(DRAG_COMPLETE);
 152 }
 153
 154 void ToplevelWindowEventHandler::ScopedWindowResizer::OnWindowDestroying(
 155     aura::Window* window) {
 156   DCHECK_EQ(resizer_->GetTarget(), window);
 157   handler_->ResizerWindowDestroyed();
 158 }
 159
 160 // ToplevelWindowEventHandler --------------------------------------------------
 161
 162 ToplevelWindowEventHandler::ToplevelWindowEventHandler()
 163     : first_finger_hittest_(HTNOWHERE),
 164       in_move_loop_(false),
 165       in_gesture_drag_(false),
 166       drag_reverted_(false),
 167       destroyed_(NULL) {
 168   Shell::GetInstance()->display_controller()->AddObserver(this);
 169 }
 170
 171 ToplevelWindowEventHandler::~ToplevelWindowEventHandler() {
 172   Shell::GetInstance()->display_controller()->RemoveObserver(this);
 173   if (destroyed_)
 174     *destroyed_ = true;
 175 }
 176
 177 void ToplevelWindowEventHandler::OnKeyEvent(ui::KeyEvent* event) {
 178   if (window_resizer_.get() && event->type() == ui::ET_KEY_PRESSED &&
 179       event->key_code() == ui::VKEY_ESCAPE) {
 180     CompleteDrag(DRAG_REVERT);
 181   }
 182 }
 183
 184 void ToplevelWindowEventHandler::OnMouseEvent(
 185     ui::MouseEvent* event) {
 186   if ((event->flags() &
 187       (ui::EF_MIDDLE_MOUSE_BUTTON | ui::EF_RIGHT_MOUSE_BUTTON)) != 0)
 188     return;
 189
 190   if (in_gesture_drag_)
 191     return;
 192
 193   aura::Window* target = static_cast<aura::Window*>(event->target());
 194   switch (event->type()) {
 195     case ui::ET_MOUSE_PRESSED:
 196       HandleMousePressed(target, event);
 197       break;
 198     case ui::ET_MOUSE_DRAGGED:
 199       HandleDrag(target, event);
 200       break;
 201     case ui::ET_MOUSE_CAPTURE_CHANGED:
 202     case ui::ET_MOUSE_RELEASED:
 203       HandleMouseReleased(target, event);
 204       break;
 205     case ui::ET_MOUSE_MOVED:
 206       HandleMouseMoved(target, event);
 207       break;
 208     case ui::ET_MOUSE_EXITED:
 209       HandleMouseExited(target, event);
 210       break;
 211     default:
 212       break;
 213   }
 214 }
 215
 216 void ToplevelWindowEventHandler::OnGestureEvent(ui::GestureEvent* event) {
 217   aura::Window* target = static_cast<aura::Window*>(event->target());
 218   if (!target->delegate())
 219     return;
 220
 221   if (window_resizer_.get() && !in_gesture_drag_)
 222     return;
 223
 224   if (window_resizer_.get() &&
 225       window_resizer_->resizer()->GetTarget() != target) {
 226     return;
 227   }
 228
 229   if (event->details().touch_points() > 2) {
 230     if (window_resizer_.get()) {
 231       CompleteDrag(DRAG_COMPLETE);
 232       event->StopPropagation();
 233     }
 234     return;
 235   }
 236
 237   switch (event->type()) {
 238     case ui::ET_GESTURE_TAP_DOWN: {
 239       int component = GetWindowComponent(target, *event);
 240       if (!(WindowResizer::GetBoundsChangeForWindowComponent(component) &
 241             WindowResizer::kBoundsChange_Resizes))
 242         return;
 243       internal::ResizeShadowController* controller =
 244           Shell::GetInstance()->resize_shadow_controller();
 245       if (controller)
 246         controller->ShowShadow(target, component);
 247       return;
 248     }
 249     case ui::ET_GESTURE_END: {
 250       internal::ResizeShadowController* controller =
 251           Shell::GetInstance()->resize_shadow_controller();
 252       if (controller)
 253         controller->HideShadow(target);
 254
 255       if (window_resizer_.get() &&
 256           (event->details().touch_points() == 1 ||
 257            !CanStartOneFingerDrag(first_finger_hittest_))) {
 258         CompleteDrag(DRAG_COMPLETE);
 259         event->StopPropagation();
 260       }
 261       return;
 262     }
 263     case ui::ET_GESTURE_BEGIN: {
 264       if (event->details().touch_points() == 1) {
 265         first_finger_hittest_ = GetWindowComponent(target, *event);
 266       } else if (window_resizer_.get()) {
 267         if (!window_resizer_->IsMove()) {
 268           // The transition from resizing with one finger to resizing with two
 269           // fingers causes unintended resizing because the location of
 270           // ET_GESTURE_SCROLL_UPDATE jumps from the position of the first
 271           // finger to the position in the middle of the two fingers. For this
 272           // reason two finger resizing is not supported.
 273           CompleteDrag(DRAG_COMPLETE);
 274           event->StopPropagation();
 275         }
 276       } else {
 277         int second_finger_hittest = GetWindowComponent(target, *event);
 278         if (CanStartTwoFingerMove(
 279                 target, first_finger_hittest_, second_finger_hittest)) {
 280           gfx::Point location_in_parent =
 281               event->details().bounding_box().CenterPoint();
 282           AttemptToStartDrag(target, location_in_parent, HTCAPTION,
 283                              aura::client::WINDOW_MOVE_SOURCE_TOUCH);
 284           event->StopPropagation();
 285         }
 286       }
 287       return;
 288     }
 289     case ui::ET_GESTURE_SCROLL_BEGIN: {
 290       // The one finger drag is not started in ET_GESTURE_BEGIN to avoid the
 291       // window jumping upon initiating a two finger drag. When a one finger
 292       // drag is converted to a two finger drag, a jump occurs because the
 293       // location of the ET_GESTURE_SCROLL_UPDATE event switches from the single
 294       // finger's position to the position in the middle of the two fingers.
 295       if (window_resizer_.get())
 296         return;
 297       int component = GetWindowComponent(target, *event);
 298       if (!CanStartOneFingerDrag(component))
 299         return;
 300       gfx::Point location_in_parent(
 301           ConvertPointToParent(target, event->location()));
 302       AttemptToStartDrag(target, location_in_parent, component,
 303                          aura::client::WINDOW_MOVE_SOURCE_TOUCH);
 304       event->StopPropagation();
 305       return;
 306     }
 307     default:
 308       break;
 309   }
 310
 311   if (!window_resizer_.get())
 312     return;
 313
 314   switch (event->type()) {
 315     case ui::ET_GESTURE_SCROLL_UPDATE:
 316       HandleDrag(target, event);
 317       event->StopPropagation();
 318       return;
 319     case ui::ET_GESTURE_SCROLL_END:
 320       // We must complete the drag here instead of as a result of ET_GESTURE_END
 321       // because otherwise the drag will be reverted when EndMoveLoop() is
 322       // called.
 323       // TODO(pkotwicz): Pass drag completion status to
 324       // WindowMoveClient::EndMoveLoop().
 325       CompleteDrag(DRAG_COMPLETE);
 326       event->StopPropagation();
 327       return;
 328     case ui::ET_SCROLL_FLING_START:
 329       CompleteDrag(DRAG_COMPLETE);
 330
 331       // TODO(pkotwicz): Fix tests which inadvertantly start flings and check
 332       // window_resizer_->IsMove() instead of the hittest component at |event|'s
 333       // location.
 334       if (GetWindowComponent(target, *event) != HTCAPTION ||
 335           !wm::GetWindowState(target)->IsNormalShowState()) {
 336         return;
 337       }
 338
 339       if (event->details().velocity_y() > kMinVertVelocityForWindowMinimize) {
 340         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_MINIMIZED);
 341       } else if (event->details().velocity_y() <
 342                  -kMinVertVelocityForWindowMinimize) {
 343         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_MAXIMIZED);
 344       } else if (event->details().velocity_x() >
 345                  kMinHorizVelocityForWindowSwipe) {
 346         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_RIGHT_SNAPPED);
 347       } else if (event->details().velocity_x() <
 348                  -kMinHorizVelocityForWindowSwipe) {
 349         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_LEFT_SNAPPED);
 350       }
 351       event->StopPropagation();
 352       return;
 353     case ui::ET_GESTURE_MULTIFINGER_SWIPE:
 354       if (!wm::GetWindowState(target)->IsNormalShowState())
 355         return;
 356
 357       CompleteDrag(DRAG_COMPLETE);
 358
 359       if (event->details().swipe_down())
 360         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_MINIMIZED);
 361       else if (event->details().swipe_up())
 362         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_MAXIMIZED);
 363       else if (event->details().swipe_right())
 364         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_RIGHT_SNAPPED);
 365       else
 366         SetWindowShowTypeFromGesture(target, wm::SHOW_TYPE_LEFT_SNAPPED);
 367       event->StopPropagation();
 368       return;
 369     default:
 370       return;
 371   }
 372 }
 373
 374 aura::client::WindowMoveResult ToplevelWindowEventHandler::RunMoveLoop(
 375     aura::Window* source,
 376     const gfx::Vector2d& drag_offset,
 377     aura::client::WindowMoveSource move_source) {
 378   DCHECK(!in_move_loop_);  // Can only handle one nested loop at a time.
 379   aura::Window* root_window = source->GetRootWindow();
 380   DCHECK(root_window);
 381   // TODO(tdresser): Use gfx::PointF. See crbug.com/337824.
 382   gfx::Point drag_location;
 383   if (move_source == aura::client::WINDOW_MOVE_SOURCE_TOUCH &&
 384       aura::Env::GetInstance()->is_touch_down()) {
 385     gfx::PointF drag_location_f;
 386     bool has_point = ui::GestureRecognizer::Get()->
 387         GetLastTouchPointForTarget(source, &drag_location_f);
 388     drag_location = gfx::ToFlooredPoint(drag_location_f);
 389     DCHECK(has_point);
 390   } else {
 391     drag_location = root_window->GetDispatcher()->GetLastMouseLocationInRoot();
 392     aura::Window::ConvertPointToTarget(
 393         root_window, source->parent(), &drag_location);
 394   }
 395   // Set the cursor before calling AttemptToStartDrag(), as that will
 396   // eventually call LockCursor() and prevent the cursor from changing.
 397   aura::client::CursorClient* cursor_client =
 398       aura::client::GetCursorClient(root_window);
 399   if (cursor_client)
 400     cursor_client->SetCursor(ui::kCursorPointer);
 401   if (!AttemptToStartDrag(source, drag_location, HTCAPTION, move_source))
 402     return aura::client::MOVE_CANCELED;
 403
 404   in_move_loop_ = true;
 405   bool destroyed = false;
 406   destroyed_ = &destroyed;
 407   base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
 408   base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
 409   base::RunLoop run_loop(aura::Env::GetInstance()->GetDispatcher());
 410   quit_closure_ = run_loop.QuitClosure();
 411   run_loop.Run();
 412   if (destroyed)
 413     return aura::client::MOVE_CANCELED;
 414   destroyed_ = NULL;
 415   in_move_loop_ = false;
 416   return drag_reverted_ ? aura::client::MOVE_CANCELED :
 417       aura::client::MOVE_SUCCESSFUL;
 418 }
 419
 420 void ToplevelWindowEventHandler::EndMoveLoop() {
 421   if (in_move_loop_)
 422     CompleteDrag(DRAG_REVERT);
 423 }
 424
 425 void ToplevelWindowEventHandler::OnDisplayConfigurationChanging() {
 426   CompleteDrag(DRAG_REVERT);
 427 }
 428
 429 bool ToplevelWindowEventHandler::AttemptToStartDrag(
 430     aura::Window* window,
 431     const gfx::Point& point_in_parent,
 432     int window_component,
 433     aura::client::WindowMoveSource source) {
 434   if (window_resizer_.get())
 435     return false;
 436   WindowResizer* resizer = CreateWindowResizer(window, point_in_parent,
 437       window_component, source).release();
 438   if (!resizer)
 439     return false;
 440
 441   window_resizer_.reset(new ScopedWindowResizer(this, resizer));
 442
 443   pre_drag_window_bounds_ = window->bounds();
 444   in_gesture_drag_ = (source == aura::client::WINDOW_MOVE_SOURCE_TOUCH);
 445   return true;
 446 }
 447
 448 void ToplevelWindowEventHandler::CompleteDrag(DragCompletionStatus status) {
 449   scoped_ptr<ScopedWindowResizer> resizer(window_resizer_.release());
 450   if (resizer) {
 451     if (status == DRAG_COMPLETE)
 452       resizer->resizer()->CompleteDrag();
 453     else
 454       resizer->resizer()->RevertDrag();
 455   }
 456   drag_reverted_ = (status == DRAG_REVERT);
 457
 458   first_finger_hittest_ = HTNOWHERE;
 459   in_gesture_drag_ = false;
 460   if (in_move_loop_)
 461     quit_closure_.Run();
 462 }
 463
 464 void ToplevelWindowEventHandler::HandleMousePressed(
 465     aura::Window* target,
 466     ui::MouseEvent* event) {
 467   if (event->phase() != ui::EP_PRETARGET)
 468     return;
 469
 470   // We also update the current window component here because for the
 471   // mouse-drag-release-press case, where the mouse is released and
 472   // pressed without mouse move event.
 473   int component = GetWindowComponent(target, *event);
 474   if ((event->flags() &
 475         (ui::EF_IS_DOUBLE_CLICK | ui::EF_IS_TRIPLE_CLICK)) == 0 &&
 476       WindowResizer::GetBoundsChangeForWindowComponent(component)) {
 477     gfx::Point location_in_parent(
 478         ConvertPointToParent(target, event->location()));
 479     AttemptToStartDrag(target, location_in_parent, component,
 480                        aura::client::WINDOW_MOVE_SOURCE_MOUSE);
 481     event->StopPropagation();
 482   } else {
 483     CompleteDrag(DRAG_COMPLETE);
 484   }
 485 }
 486
 487 void ToplevelWindowEventHandler::HandleMouseReleased(
 488     aura::Window* target,
 489     ui::MouseEvent* event) {
 490   if (event->phase() != ui::EP_PRETARGET)
 491     return;
 492
 493   CompleteDrag(event->type() == ui::ET_MOUSE_RELEASED ?
 494                    DRAG_COMPLETE : DRAG_REVERT);
 495   // Completing the drag may result in hiding the window. If this happens
 496   // return true so no other handlers/observers see the event. Otherwise
 497   // they see the event on a hidden window.
 498   if (event->type() == ui::ET_MOUSE_CAPTURE_CHANGED &&
 499       !target->IsVisible()) {
 500     event->StopPropagation();
 501   }
 502 }
 503
 504 void ToplevelWindowEventHandler::HandleDrag(
 505     aura::Window* target,
 506     ui::LocatedEvent* event) {
 507   // This function only be triggered to move window
 508   // by mouse drag or touch move event.
 509   DCHECK(event->type() == ui::ET_MOUSE_DRAGGED ||
 510          event->type() == ui::ET_TOUCH_MOVED ||
 511          event->type() == ui::ET_GESTURE_SCROLL_UPDATE);
 512
 513   // Drag actions are performed pre-target handling to prevent spurious mouse
 514   // moves from the move/size operation from being sent to the target.
 515   if (event->phase() != ui::EP_PRETARGET)
 516     return;
 517
 518   if (!window_resizer_)
 519     return;
 520   window_resizer_->resizer()->Drag(
 521       ConvertPointToParent(target, event->location()), event->flags());
 522   event->StopPropagation();
 523 }
 524
 525 void ToplevelWindowEventHandler::HandleMouseMoved(
 526     aura::Window* target,
 527     ui::LocatedEvent* event) {
 528   // Shadow effects are applied after target handling. Note that we don't
 529   // respect ER_HANDLED here right now since we have not had a reason to allow
 530   // the target to cancel shadow rendering.
 531   if (event->phase() != ui::EP_POSTTARGET)
 532     return;
 533
 534   // TODO(jamescook): Move the resize cursor update code into here from
 535   // CompoundEventFilter?
 536   internal::ResizeShadowController* controller =
 537       Shell::GetInstance()->resize_shadow_controller();
 538   if (controller) {
 539     if (event->flags() & ui::EF_IS_NON_CLIENT) {
 540       int component =
 541           target->delegate()->GetNonClientComponent(event->location());
 542       controller->ShowShadow(target, component);
 543     } else {
 544       controller->HideShadow(target);
 545     }
 546   }
 547 }
 548
 549 void ToplevelWindowEventHandler::HandleMouseExited(
 550     aura::Window* target,
 551     ui::LocatedEvent* event) {
 552   // Shadow effects are applied after target handling. Note that we don't
 553   // respect ER_HANDLED here right now since we have not had a reason to allow
 554   // the target to cancel shadow rendering.
 555   if (event->phase() != ui::EP_POSTTARGET)
 556     return;
 557
 558   internal::ResizeShadowController* controller =
 559       Shell::GetInstance()->resize_shadow_controller();
 560   if (controller)
 561     controller->HideShadow(target);
 562 }
 563
 564 void ToplevelWindowEventHandler::SetWindowShowTypeFromGesture(
 565     aura::Window* window,
 566     wm::WindowShowType new_show_type) {
 567   wm::WindowState* window_state = ash::wm::GetWindowState(window);
 568   switch (new_show_type) {
 569     case wm::SHOW_TYPE_MINIMIZED:
 570       if (window_state->CanMinimize()) {
 571         window_state->Minimize();
 572         window_state->set_always_restores_to_restore_bounds(true);
 573         window_state->SetRestoreBoundsInParent(pre_drag_window_bounds_);
 574       }
 575       break;
 576     case wm::SHOW_TYPE_MAXIMIZED:
 577       if (window_state->CanMaximize()) {
 578         window_state->SetRestoreBoundsInParent(pre_drag_window_bounds_);
 579         window_state->Maximize();
 580       }
 581       break;
 582     case wm::SHOW_TYPE_LEFT_SNAPPED:
 583       if (window_state->CanSnap()) {
 584         window_state->SetRestoreBoundsInParent(pre_drag_window_bounds_);
 585         internal::SnapSizer::SnapWindow(window_state,
 586                                         internal::SnapSizer::LEFT_EDGE);
 587       }
 588       break;
 589     case wm::SHOW_TYPE_RIGHT_SNAPPED:
 590       if (window_state->CanSnap()) {
 591         window_state->SetRestoreBoundsInParent(pre_drag_window_bounds_);
 592         internal::SnapSizer::SnapWindow(window_state,
 593                                         internal::SnapSizer::RIGHT_EDGE);
 594       }
 595       break;
 596     default:
 597       NOTREACHED();
 598   }
 599 }
 600
 601 void ToplevelWindowEventHandler::ResizerWindowDestroyed() {
 602   // We explicitly don't invoke RevertDrag() since that may do things to window.
 603   // Instead we destroy the resizer.
 604   window_resizer_.reset();
 605
 606   CompleteDrag(DRAG_REVERT);
 607 }
 608
 609 }  // namespace ash