ui/views/widget/root_view.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 "ui/views/widget/root_view.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/logging.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "ui/accessibility/ax_view_state.h"
  12 #include "ui/base/cursor/cursor.h"
  13 #include "ui/base/dragdrop/drag_drop_types.h"
  14 #include "ui/base/ui_base_switches_util.h"
  15 #include "ui/compositor/layer.h"
  16 #include "ui/events/event.h"
  17 #include "ui/events/keycodes/keyboard_codes.h"
  18 #include "ui/gfx/canvas.h"
  19 #include "ui/views/drag_controller.h"
  20 #include "ui/views/focus/view_storage.h"
  21 #include "ui/views/layout/fill_layout.h"
  22 #include "ui/views/view_targeter.h"
  23 #include "ui/views/widget/root_view_targeter.h"
  24 #include "ui/views/widget/widget.h"
  25 #include "ui/views/widget/widget_delegate.h"
  26
  27 typedef ui::EventDispatchDetails DispatchDetails;
  28
  29 namespace views {
  30 namespace internal {
  31
  32 namespace {
  33
  34 enum EventType {
  35   EVENT_ENTER,
  36   EVENT_EXIT
  37 };
  38
  39 class MouseEnterExitEvent : public ui::MouseEvent {
  40  public:
  41   MouseEnterExitEvent(const ui::MouseEvent& event, ui::EventType type)
  42       : ui::MouseEvent(event,
  43                        static_cast<View*>(NULL),
  44                        static_cast<View*>(NULL)) {
  45     DCHECK(type == ui::ET_MOUSE_ENTERED ||
  46            type == ui::ET_MOUSE_EXITED);
  47     SetType(type);
  48   }
  49
  50   virtual ~MouseEnterExitEvent() {}
  51 };
  52
  53 }  // namespace
  54
  55 // This event handler receives events in the pre-target phase and takes care of
  56 // the following:
  57 //   - Shows keyboard-triggered context menus.
  58 class PreEventDispatchHandler : public ui::EventHandler {
  59  public:
  60   explicit PreEventDispatchHandler(View* owner)
  61       : owner_(owner) {
  62   }
  63   virtual ~PreEventDispatchHandler() {}
  64
  65  private:
  66   // ui::EventHandler:
  67   virtual void OnKeyEvent(ui::KeyEvent* event) override {
  68     CHECK_EQ(ui::EP_PRETARGET, event->phase());
  69     if (event->handled())
  70       return;
  71
  72     View* v = NULL;
  73     if (owner_->GetFocusManager())  // Can be NULL in unittests.
  74       v = owner_->GetFocusManager()->GetFocusedView();
  75
  76     // Special case to handle keyboard-triggered context menus.
  77     if (v && v->enabled() && ((event->key_code() == ui::VKEY_APPS) ||
  78        (event->key_code() == ui::VKEY_F10 && event->IsShiftDown()))) {
  79       // Clamp the menu location within the visible bounds of each ancestor view
  80       // to avoid showing the menu over a completely different view or window.
  81       gfx::Point location = v->GetKeyboardContextMenuLocation();
  82       for (View* parent = v->parent(); parent; parent = parent->parent()) {
  83         const gfx::Rect& parent_bounds = parent->GetBoundsInScreen();
  84         location.SetToMax(parent_bounds.origin());
  85         location.SetToMin(parent_bounds.bottom_right());
  86       }
  87       v->ShowContextMenu(location, ui::MENU_SOURCE_KEYBOARD);
  88       event->StopPropagation();
  89     }
  90   }
  91
  92   View* owner_;
  93
  94   DISALLOW_COPY_AND_ASSIGN(PreEventDispatchHandler);
  95 };
  96
  97 // This event handler receives events in the post-target phase and takes care of
  98 // the following:
  99 //   - Generates context menu, or initiates drag-and-drop, from gesture events.
 100 class PostEventDispatchHandler : public ui::EventHandler {
 101  public:
 102   PostEventDispatchHandler()
 103       : touch_dnd_enabled_(::switches::IsTouchDragDropEnabled()) {
 104   }
 105   virtual ~PostEventDispatchHandler() {}
 106
 107  private:
 108   // Overridden from ui::EventHandler:
 109   virtual void OnGestureEvent(ui::GestureEvent* event) override {
 110     DCHECK_EQ(ui::EP_POSTTARGET, event->phase());
 111     if (event->handled())
 112       return;
 113
 114     View* target = static_cast<View*>(event->target());
 115     gfx::Point location = event->location();
 116     if (touch_dnd_enabled_ &&
 117         event->type() == ui::ET_GESTURE_LONG_PRESS &&
 118         (!target->drag_controller() ||
 119          target->drag_controller()->CanStartDragForView(
 120              target, location, location))) {
 121       if (target->DoDrag(*event, location,
 122           ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH)) {
 123         event->StopPropagation();
 124         return;
 125       }
 126     }
 127
 128     if (target->context_menu_controller() &&
 129         (event->type() == ui::ET_GESTURE_LONG_PRESS ||
 130          event->type() == ui::ET_GESTURE_LONG_TAP ||
 131          event->type() == ui::ET_GESTURE_TWO_FINGER_TAP)) {
 132       gfx::Point screen_location(location);
 133       View::ConvertPointToScreen(target, &screen_location);
 134       target->ShowContextMenu(screen_location, ui::MENU_SOURCE_TOUCH);
 135       event->StopPropagation();
 136     }
 137   }
 138
 139   bool touch_dnd_enabled_;
 140
 141   DISALLOW_COPY_AND_ASSIGN(PostEventDispatchHandler);
 142 };
 143
 144 // static
 145 const char RootView::kViewClassName[] = "RootView";
 146
 147 ////////////////////////////////////////////////////////////////////////////////
 148 // RootView, public:
 149
 150 // Creation and lifetime -------------------------------------------------------
 151
 152 RootView::RootView(Widget* widget)
 153     : widget_(widget),
 154       mouse_pressed_handler_(NULL),
 155       mouse_move_handler_(NULL),
 156       last_click_handler_(NULL),
 157       explicit_mouse_handler_(false),
 158       last_mouse_event_flags_(0),
 159       last_mouse_event_x_(-1),
 160       last_mouse_event_y_(-1),
 161       gesture_handler_(NULL),
 162       gesture_handler_set_before_processing_(false),
 163       pre_dispatch_handler_(new internal::PreEventDispatchHandler(this)),
 164       post_dispatch_handler_(new internal::PostEventDispatchHandler),
 165       focus_search_(this, false, false),
 166       focus_traversable_parent_(NULL),
 167       focus_traversable_parent_view_(NULL),
 168       event_dispatch_target_(NULL),
 169       old_dispatch_target_(NULL) {
 170   AddPreTargetHandler(pre_dispatch_handler_.get());
 171   AddPostTargetHandler(post_dispatch_handler_.get());
 172   SetEventTargeter(scoped_ptr<ViewTargeter>(new RootViewTargeter(this, this)));
 173 }
 174
 175 RootView::~RootView() {
 176   // If we have children remove them explicitly so to make sure a remove
 177   // notification is sent for each one of them.
 178   if (has_children())
 179     RemoveAllChildViews(true);
 180 }
 181
 182 // Tree operations -------------------------------------------------------------
 183
 184 void RootView::SetContentsView(View* contents_view) {
 185   DCHECK(contents_view && GetWidget()->native_widget()) <<
 186       "Can't be called until after the native widget is created!";
 187   // The ContentsView must be set up _after_ the window is created so that its
 188   // Widget pointer is valid.
 189   SetLayoutManager(new FillLayout);
 190   if (has_children())
 191     RemoveAllChildViews(true);
 192   AddChildView(contents_view);
 193
 194   // Force a layout now, since the attached hierarchy won't be ready for the
 195   // containing window's bounds. Note that we call Layout directly rather than
 196   // calling the widget's size changed handler, since the RootView's bounds may
 197   // not have changed, which will cause the Layout not to be done otherwise.
 198   Layout();
 199 }
 200
 201 View* RootView::GetContentsView() {
 202   return child_count() > 0 ? child_at(0) : NULL;
 203 }
 204
 205 void RootView::NotifyNativeViewHierarchyChanged() {
 206   PropagateNativeViewHierarchyChanged();
 207 }
 208
 209 // Focus -----------------------------------------------------------------------
 210
 211 void RootView::SetFocusTraversableParent(FocusTraversable* focus_traversable) {
 212   DCHECK(focus_traversable != this);
 213   focus_traversable_parent_ = focus_traversable;
 214 }
 215
 216 void RootView::SetFocusTraversableParentView(View* view) {
 217   focus_traversable_parent_view_ = view;
 218 }
 219
 220 // System events ---------------------------------------------------------------
 221
 222 void RootView::ThemeChanged() {
 223   View::PropagateThemeChanged();
 224 }
 225
 226 void RootView::LocaleChanged() {
 227   View::PropagateLocaleChanged();
 228 }
 229
 230 ////////////////////////////////////////////////////////////////////////////////
 231 // RootView, FocusTraversable implementation:
 232
 233 FocusSearch* RootView::GetFocusSearch() {
 234   return &focus_search_;
 235 }
 236
 237 FocusTraversable* RootView::GetFocusTraversableParent() {
 238   return focus_traversable_parent_;
 239 }
 240
 241 View* RootView::GetFocusTraversableParentView() {
 242   return focus_traversable_parent_view_;
 243 }
 244
 245 ////////////////////////////////////////////////////////////////////////////////
 246 // RootView, ui::EventProcessor overrides:
 247
 248 ui::EventTarget* RootView::GetRootTarget() {
 249   return this;
 250 }
 251
 252 void RootView::OnEventProcessingStarted(ui::Event* event) {
 253   if (!event->IsGestureEvent())
 254     return;
 255
 256   ui::GestureEvent* gesture_event = event->AsGestureEvent();
 257
 258   // Do not process ui::ET_GESTURE_BEGIN events.
 259   if (gesture_event->type() == ui::ET_GESTURE_BEGIN) {
 260     event->SetHandled();
 261     return;
 262   }
 263
 264   // Do not process ui::ET_GESTURE_END events if they do not correspond to the
 265   // removal of the final touch point or if no gesture handler has already
 266   // been set.
 267   if (gesture_event->type() == ui::ET_GESTURE_END &&
 268       (gesture_event->details().touch_points() > 1 ||
 269        !gesture_handler_)) {
 270     event->SetHandled();
 271     return;
 272   }
 273
 274   // Do not process subsequent gesture scroll events if no handler was set for
 275   // a ui::ET_GESTURE_SCROLL_BEGIN event.
 276   if (!gesture_handler_ &&
 277       (gesture_event->type() == ui::ET_GESTURE_SCROLL_UPDATE ||
 278        gesture_event->type() == ui::ET_GESTURE_SCROLL_END ||
 279        gesture_event->type() == ui::ET_SCROLL_FLING_START)) {
 280     event->SetHandled();
 281     return;
 282   }
 283
 284   gesture_handler_set_before_processing_ = !!gesture_handler_;
 285 }
 286
 287 void RootView::OnEventProcessingFinished(ui::Event* event) {
 288   // If |event| was not handled and |gesture_handler_| was not set by the
 289   // dispatch of a previous gesture event, then no default gesture handler
 290   // should be set prior to the next gesture event being received.
 291   if (event->IsGestureEvent() &&
 292       !event->handled() &&
 293       !gesture_handler_set_before_processing_) {
 294     gesture_handler_ = NULL;
 295   }
 296 }
 297
 298 ////////////////////////////////////////////////////////////////////////////////
 299 // RootView, View overrides:
 300
 301 const Widget* RootView::GetWidget() const {
 302   return widget_;
 303 }
 304
 305 Widget* RootView::GetWidget() {
 306   return const_cast<Widget*>(const_cast<const RootView*>(this)->GetWidget());
 307 }
 308
 309 bool RootView::IsDrawn() const {
 310   return visible();
 311 }
 312
 313 void RootView::Layout() {
 314   View::Layout();
 315   widget_->OnRootViewLayout();
 316 }
 317
 318 const char* RootView::GetClassName() const {
 319   return kViewClassName;
 320 }
 321
 322 void RootView::SchedulePaintInRect(const gfx::Rect& rect) {
 323   if (layer()) {
 324     layer()->SchedulePaint(rect);
 325   } else {
 326     gfx::Rect xrect = ConvertRectToParent(rect);
 327     gfx::Rect invalid_rect = gfx::IntersectRects(GetLocalBounds(), xrect);
 328     if (!invalid_rect.IsEmpty())
 329       widget_->SchedulePaintInRect(invalid_rect);
 330   }
 331 }
 332
 333 bool RootView::OnMousePressed(const ui::MouseEvent& event) {
 334   UpdateCursor(event);
 335   SetMouseLocationAndFlags(event);
 336
 337   // If mouse_pressed_handler_ is non null, we are currently processing
 338   // a pressed -> drag -> released session. In that case we send the
 339   // event to mouse_pressed_handler_
 340   if (mouse_pressed_handler_) {
 341     ui::MouseEvent mouse_pressed_event(event, static_cast<View*>(this),
 342                                        mouse_pressed_handler_);
 343     drag_info_.Reset();
 344     ui::EventDispatchDetails dispatch_details =
 345         DispatchEvent(mouse_pressed_handler_, &mouse_pressed_event);
 346     if (dispatch_details.dispatcher_destroyed)
 347       return true;
 348     return true;
 349   }
 350   DCHECK(!explicit_mouse_handler_);
 351
 352   bool hit_disabled_view = false;
 353   // Walk up the tree until we find a view that wants the mouse event.
 354   for (mouse_pressed_handler_ = GetEventHandlerForPoint(event.location());
 355        mouse_pressed_handler_ && (mouse_pressed_handler_ != this);
 356        mouse_pressed_handler_ = mouse_pressed_handler_->parent()) {
 357     DVLOG(1) << "OnMousePressed testing "
 358         << mouse_pressed_handler_->GetClassName();
 359     if (!mouse_pressed_handler_->enabled()) {
 360       // Disabled views should eat events instead of propagating them upwards.
 361       hit_disabled_view = true;
 362       break;
 363     }
 364
 365     // See if this view wants to handle the mouse press.
 366     ui::MouseEvent mouse_pressed_event(event, static_cast<View*>(this),
 367                                        mouse_pressed_handler_);
 368
 369     // Remove the double-click flag if the handler is different than the
 370     // one which got the first click part of the double-click.
 371     if (mouse_pressed_handler_ != last_click_handler_)
 372       mouse_pressed_event.set_flags(event.flags() & ~ui::EF_IS_DOUBLE_CLICK);
 373
 374     drag_info_.Reset();
 375     ui::EventDispatchDetails dispatch_details =
 376         DispatchEvent(mouse_pressed_handler_, &mouse_pressed_event);
 377     if (dispatch_details.dispatcher_destroyed)
 378       return mouse_pressed_event.handled();
 379
 380     // The view could have removed itself from the tree when handling
 381     // OnMousePressed().  In this case, the removal notification will have
 382     // reset mouse_pressed_handler_ to NULL out from under us.  Detect this
 383     // case and stop.  (See comments in view.h.)
 384     //
 385     // NOTE: Don't return true here, because we don't want the frame to
 386     // forward future events to us when there's no handler.
 387     if (!mouse_pressed_handler_)
 388       break;
 389
 390     // If the view handled the event, leave mouse_pressed_handler_ set and
 391     // return true, which will cause subsequent drag/release events to get
 392     // forwarded to that view.
 393     if (mouse_pressed_event.handled()) {
 394       last_click_handler_ = mouse_pressed_handler_;
 395       DVLOG(1) << "OnMousePressed handled by "
 396           << mouse_pressed_handler_->GetClassName();
 397       return true;
 398     }
 399   }
 400
 401   // Reset mouse_pressed_handler_ to indicate that no processing is occurring.
 402   mouse_pressed_handler_ = NULL;
 403
 404   // In the event that a double-click is not handled after traversing the
 405   // entire hierarchy (even as a single-click when sent to a different view),
 406   // it must be marked as handled to avoid anything happening from default
 407   // processing if it the first click-part was handled by us.
 408   if (last_click_handler_ && (event.flags() & ui::EF_IS_DOUBLE_CLICK))
 409     hit_disabled_view = true;
 410
 411   last_click_handler_ = NULL;
 412   return hit_disabled_view;
 413 }
 414
 415 bool RootView::OnMouseDragged(const ui::MouseEvent& event) {
 416   CHECK_EQ(ui::ET_MOUSE_DRAGGED, event.type());
 417   if (mouse_pressed_handler_) {
 418     SetMouseLocationAndFlags(event);
 419
 420     ui::MouseEvent mouse_event(event, static_cast<View*>(this),
 421                                mouse_pressed_handler_);
 422     ui::EventDispatchDetails dispatch_details =
 423         DispatchEvent(mouse_pressed_handler_, &mouse_event);
 424     if (dispatch_details.dispatcher_destroyed)
 425       return false;
 426   }
 427   return false;
 428 }
 429
 430 void RootView::OnMouseReleased(const ui::MouseEvent& event) {
 431   UpdateCursor(event);
 432
 433   if (mouse_pressed_handler_) {
 434     ui::MouseEvent mouse_released(event, static_cast<View*>(this),
 435                                   mouse_pressed_handler_);
 436     // We allow the view to delete us from the event dispatch callback. As such,
 437     // configure state such that we're done first, then call View.
 438     View* mouse_pressed_handler = mouse_pressed_handler_;
 439     SetMouseHandler(NULL);
 440     ui::EventDispatchDetails dispatch_details =
 441         DispatchEvent(mouse_pressed_handler, &mouse_released);
 442     if (dispatch_details.dispatcher_destroyed)
 443       return;
 444   }
 445 }
 446
 447 void RootView::OnMouseCaptureLost() {
 448   // TODO: this likely needs to reset touch handler too.
 449
 450   if (mouse_pressed_handler_ || gesture_handler_) {
 451     // Synthesize a release event for UpdateCursor.
 452     if (mouse_pressed_handler_) {
 453       gfx::Point last_point(last_mouse_event_x_, last_mouse_event_y_);
 454       ui::MouseEvent release_event(ui::ET_MOUSE_RELEASED,
 455                                    last_point, last_point,
 456                                    last_mouse_event_flags_,
 457                                    0);
 458       UpdateCursor(release_event);
 459     }
 460     // We allow the view to delete us from OnMouseCaptureLost. As such,
 461     // configure state such that we're done first, then call View.
 462     View* mouse_pressed_handler = mouse_pressed_handler_;
 463     View* gesture_handler = gesture_handler_;
 464     SetMouseHandler(NULL);
 465     if (mouse_pressed_handler)
 466       mouse_pressed_handler->OnMouseCaptureLost();
 467     else
 468       gesture_handler->OnMouseCaptureLost();
 469     // WARNING: we may have been deleted.
 470   }
 471 }
 472
 473 void RootView::OnMouseMoved(const ui::MouseEvent& event) {
 474   CHECK_EQ(ui::ET_MOUSE_MOVED, event.type());
 475   View* v = GetEventHandlerForPoint(event.location());
 476   // Find the first enabled view, or the existing move handler, whichever comes
 477   // first.  The check for the existing handler is because if a view becomes
 478   // disabled while handling moves, it's wrong to suddenly send ET_MOUSE_EXITED
 479   // and ET_MOUSE_ENTERED events, because the mouse hasn't actually exited yet.
 480   while (v && !v->enabled() && (v != mouse_move_handler_))
 481     v = v->parent();
 482   if (v && v != this) {
 483     if (v != mouse_move_handler_) {
 484       if (mouse_move_handler_ != NULL &&
 485           (!mouse_move_handler_->notify_enter_exit_on_child() ||
 486            !mouse_move_handler_->Contains(v))) {
 487         MouseEnterExitEvent exit(event, ui::ET_MOUSE_EXITED);
 488         exit.ConvertLocationToTarget(static_cast<View*>(this),
 489                                      mouse_move_handler_);
 490         ui::EventDispatchDetails dispatch_details =
 491             DispatchEvent(mouse_move_handler_, &exit);
 492         if (dispatch_details.dispatcher_destroyed)
 493           return;
 494         NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 495             mouse_move_handler_, v);
 496       }
 497       View* old_handler = mouse_move_handler_;
 498       mouse_move_handler_ = v;
 499       if (!mouse_move_handler_->notify_enter_exit_on_child() ||
 500           !mouse_move_handler_->Contains(old_handler)) {
 501         MouseEnterExitEvent entered(event, ui::ET_MOUSE_ENTERED);
 502         entered.ConvertLocationToTarget(static_cast<View*>(this),
 503                                         mouse_move_handler_);
 504         ui::EventDispatchDetails dispatch_details =
 505             DispatchEvent(mouse_move_handler_, &entered);
 506         if (dispatch_details.dispatcher_destroyed)
 507           return;
 508         NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_ENTERED,
 509             mouse_move_handler_, old_handler);
 510       }
 511     }
 512     ui::MouseEvent moved_event(event, static_cast<View*>(this),
 513                                mouse_move_handler_);
 514     mouse_move_handler_->OnMouseMoved(moved_event);
 515     // TODO(tdanderson): It may be possible to avoid setting the cursor twice
 516     //                   (once here and once from CompoundEventFilter) on a
 517     //                   mousemove. See crbug.com/351469.
 518     if (!(moved_event.flags() & ui::EF_IS_NON_CLIENT))
 519       widget_->SetCursor(mouse_move_handler_->GetCursor(moved_event));
 520   } else if (mouse_move_handler_ != NULL) {
 521     MouseEnterExitEvent exited(event, ui::ET_MOUSE_EXITED);
 522     ui::EventDispatchDetails dispatch_details =
 523         DispatchEvent(mouse_move_handler_, &exited);
 524     if (dispatch_details.dispatcher_destroyed)
 525       return;
 526     NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 527         mouse_move_handler_, v);
 528     // On Aura the non-client area extends slightly outside the root view for
 529     // some windows.  Let the non-client cursor handling code set the cursor
 530     // as we do above.
 531     if (!(event.flags() & ui::EF_IS_NON_CLIENT))
 532       widget_->SetCursor(gfx::kNullCursor);
 533     mouse_move_handler_ = NULL;
 534   }
 535 }
 536
 537 void RootView::OnMouseExited(const ui::MouseEvent& event) {
 538   if (mouse_move_handler_ != NULL) {
 539     MouseEnterExitEvent exited(event, ui::ET_MOUSE_EXITED);
 540     ui::EventDispatchDetails dispatch_details =
 541         DispatchEvent(mouse_move_handler_, &exited);
 542     if (dispatch_details.dispatcher_destroyed)
 543       return;
 544     NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 545         mouse_move_handler_, NULL);
 546     mouse_move_handler_ = NULL;
 547   }
 548 }
 549
 550 bool RootView::OnMouseWheel(const ui::MouseWheelEvent& event) {
 551   for (View* v = GetEventHandlerForPoint(event.location());
 552        v && v != this && !event.handled(); v = v->parent()) {
 553     ui::EventDispatchDetails dispatch_details =
 554         DispatchEvent(v, const_cast<ui::MouseWheelEvent*>(&event));
 555     if (dispatch_details.dispatcher_destroyed ||
 556         dispatch_details.target_destroyed) {
 557       return event.handled();
 558     }
 559   }
 560   return event.handled();
 561 }
 562
 563 void RootView::SetMouseHandler(View* new_mh) {
 564   // If we're clearing the mouse handler, clear explicit_mouse_handler_ as well.
 565   explicit_mouse_handler_ = (new_mh != NULL);
 566   mouse_pressed_handler_ = new_mh;
 567   gesture_handler_ = new_mh;
 568   drag_info_.Reset();
 569 }
 570
 571 void RootView::GetAccessibleState(ui::AXViewState* state) {
 572   state->name = widget_->widget_delegate()->GetAccessibleWindowTitle();
 573   state->role = widget_->widget_delegate()->GetAccessibleWindowRole();
 574 }
 575
 576 void RootView::UpdateParentLayer() {
 577   if (layer())
 578     ReparentLayer(gfx::Vector2d(GetMirroredX(), y()), widget_->GetLayer());
 579 }
 580
 581 ////////////////////////////////////////////////////////////////////////////////
 582 // RootView, protected:
 583
 584 void RootView::ViewHierarchyChanged(
 585     const ViewHierarchyChangedDetails& details) {
 586   widget_->ViewHierarchyChanged(details);
 587
 588   if (!details.is_add) {
 589     if (!explicit_mouse_handler_ && mouse_pressed_handler_ == details.child)
 590       mouse_pressed_handler_ = NULL;
 591     if (mouse_move_handler_ == details.child)
 592       mouse_move_handler_ = NULL;
 593     if (gesture_handler_ == details.child)
 594       gesture_handler_ = NULL;
 595     if (event_dispatch_target_ == details.child)
 596       event_dispatch_target_ = NULL;
 597     if (old_dispatch_target_ == details.child)
 598       old_dispatch_target_ = NULL;
 599   }
 600 }
 601
 602 void RootView::VisibilityChanged(View* /*starting_from*/, bool is_visible) {
 603   if (!is_visible) {
 604     // When the root view is being hidden (e.g. when widget is minimized)
 605     // handlers are reset, so that after it is reshown, events are not captured
 606     // by old handlers.
 607     explicit_mouse_handler_ = false;
 608     mouse_pressed_handler_ = NULL;
 609     mouse_move_handler_ = NULL;
 610     gesture_handler_ = NULL;
 611     event_dispatch_target_ = NULL;
 612     old_dispatch_target_ = NULL;
 613   }
 614 }
 615
 616 void RootView::OnPaint(gfx::Canvas* canvas) {
 617   if (!layer() || !layer()->fills_bounds_opaquely())
 618     canvas->DrawColor(SK_ColorBLACK, SkXfermode::kClear_Mode);
 619
 620   View::OnPaint(canvas);
 621 }
 622
 623 gfx::Vector2d RootView::CalculateOffsetToAncestorWithLayer(
 624     ui::Layer** layer_parent) {
 625   gfx::Vector2d offset(View::CalculateOffsetToAncestorWithLayer(layer_parent));
 626   if (!layer() && layer_parent)
 627     *layer_parent = widget_->GetLayer();
 628   return offset;
 629 }
 630
 631 View::DragInfo* RootView::GetDragInfo() {
 632   return &drag_info_;
 633 }
 634
 635 ////////////////////////////////////////////////////////////////////////////////
 636 // RootView, private:
 637
 638 // Input -----------------------------------------------------------------------
 639
 640 void RootView::UpdateCursor(const ui::MouseEvent& event) {
 641   if (!(event.flags() & ui::EF_IS_NON_CLIENT)) {
 642     View* v = GetEventHandlerForPoint(event.location());
 643     ui::MouseEvent me(event, static_cast<View*>(this), v);
 644     widget_->SetCursor(v->GetCursor(me));
 645   }
 646 }
 647
 648 void RootView::SetMouseLocationAndFlags(const ui::MouseEvent& event) {
 649   last_mouse_event_flags_ = event.flags();
 650   last_mouse_event_x_ = event.x();
 651   last_mouse_event_y_ = event.y();
 652 }
 653
 654 void RootView::NotifyEnterExitOfDescendant(const ui::MouseEvent& event,
 655                                            ui::EventType type,
 656                                            View* view,
 657                                            View* sibling) {
 658   for (View* p = view->parent(); p; p = p->parent()) {
 659     if (!p->notify_enter_exit_on_child())
 660       continue;
 661     if (sibling && p->Contains(sibling))
 662       break;
 663     // It is necessary to recreate the notify-event for each dispatch, since one
 664     // of the callbacks can mark the event as handled, and that would cause
 665     // incorrect event dispatch.
 666     MouseEnterExitEvent notify_event(event, type);
 667     ui::EventDispatchDetails dispatch_details = DispatchEvent(p, &notify_event);
 668     if (dispatch_details.dispatcher_destroyed ||
 669         dispatch_details.target_destroyed) {
 670       return;
 671     }
 672   }
 673 }
 674
 675 bool RootView::CanDispatchToTarget(ui::EventTarget* target) {
 676   return event_dispatch_target_ == target;
 677 }
 678
 679 ui::EventDispatchDetails RootView::PreDispatchEvent(ui::EventTarget* target,
 680                                                     ui::Event* event) {
 681   View* view = static_cast<View*>(target);
 682   if (event->IsGestureEvent()) {
 683     // Update |gesture_handler_| to indicate which View is currently handling
 684     // gesture events.
 685     // TODO(tdanderson): Look into moving this to PostDispatchEvent() and
 686     //                   using |event_dispatch_target_| instead of
 687     //                   |gesture_handler_| to detect if the view has been
 688     //                   removed from the tree.
 689     gesture_handler_ = view;
 690
 691     // Disabled views are permitted to be targets of gesture events, but
 692     // gesture events should never actually be dispatched to them. Prevent
 693     // dispatch by marking the event as handled.
 694     if (!view->enabled())
 695       event->SetHandled();
 696   }
 697
 698   old_dispatch_target_ = event_dispatch_target_;
 699   event_dispatch_target_ = view;
 700   return DispatchDetails();
 701 }
 702
 703 ui::EventDispatchDetails RootView::PostDispatchEvent(ui::EventTarget* target,
 704                                                      const ui::Event& event) {
 705   // The GESTURE_END event corresponding to the removal of the final touch
 706   // point marks the end of a gesture sequence, so reset |gesture_handler_|
 707   // to NULL.
 708   if (event.type() == ui::ET_GESTURE_END) {
 709     // In case a drag was in progress, reset all the handlers. Otherwise, just
 710     // reset the gesture handler.
 711     if (gesture_handler_ && gesture_handler_ == mouse_pressed_handler_)
 712       SetMouseHandler(NULL);
 713     else
 714       gesture_handler_ = NULL;
 715   }
 716
 717   DispatchDetails details;
 718   if (target != event_dispatch_target_)
 719     details.target_destroyed = true;
 720
 721   event_dispatch_target_ = old_dispatch_target_;
 722   old_dispatch_target_ = NULL;
 723
 724 #ifndef NDEBUG
 725   DCHECK(!event_dispatch_target_ || Contains(event_dispatch_target_));
 726 #endif
 727
 728   return details;
 729 }
 730
 731 }  // namespace internal
 732 }  // namespace views