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/views_switches.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       scroll_gesture_handler_(NULL),
 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 ViewTargeter(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 ui::EventDispatchDetails RootView::OnEventFromSource(ui::Event* event) {
 253   // TODO(tdanderson): Replace the calls to Dispatch*Event() with calls to
 254   //                   EventProcessor::OnEventFromSource() once the code for
 255   //                   that event type has been refactored, and then
 256   //                   eventually remove this function altogether. See
 257   //                   crbug.com/348083.
 258   if (event->IsKeyEvent())
 259     return EventProcessor::OnEventFromSource(event);
 260   else if (event->IsScrollEvent())
 261     return EventProcessor::OnEventFromSource(event);
 262   else if (event->IsTouchEvent())
 263     NOTREACHED() << "Touch events should not be sent to RootView.";
 264   else if (event->IsGestureEvent())
 265     DispatchGestureEvent(event->AsGestureEvent());
 266   else if (event->IsMouseEvent())
 267     NOTREACHED() << "Should not be called with a MouseEvent.";
 268   else
 269     NOTREACHED() << "Invalid event type.";
 270
 271   return DispatchDetails();
 272 }
 273
 274 ////////////////////////////////////////////////////////////////////////////////
 275 // RootView, View overrides:
 276
 277 const Widget* RootView::GetWidget() const {
 278   return widget_;
 279 }
 280
 281 Widget* RootView::GetWidget() {
 282   return const_cast<Widget*>(const_cast<const RootView*>(this)->GetWidget());
 283 }
 284
 285 bool RootView::IsDrawn() const {
 286   return visible();
 287 }
 288
 289 void RootView::Layout() {
 290   View::Layout();
 291   widget_->OnRootViewLayout();
 292 }
 293
 294 const char* RootView::GetClassName() const {
 295   return kViewClassName;
 296 }
 297
 298 void RootView::SchedulePaintInRect(const gfx::Rect& rect) {
 299   if (layer()) {
 300     layer()->SchedulePaint(rect);
 301   } else {
 302     gfx::Rect xrect = ConvertRectToParent(rect);
 303     gfx::Rect invalid_rect = gfx::IntersectRects(GetLocalBounds(), xrect);
 304     if (!invalid_rect.IsEmpty())
 305       widget_->SchedulePaintInRect(invalid_rect);
 306   }
 307 }
 308
 309 bool RootView::OnMousePressed(const ui::MouseEvent& event) {
 310   UpdateCursor(event);
 311   SetMouseLocationAndFlags(event);
 312
 313   // If mouse_pressed_handler_ is non null, we are currently processing
 314   // a pressed -> drag -> released session. In that case we send the
 315   // event to mouse_pressed_handler_
 316   if (mouse_pressed_handler_) {
 317     ui::MouseEvent mouse_pressed_event(event, static_cast<View*>(this),
 318                                        mouse_pressed_handler_);
 319     drag_info_.Reset();
 320     ui::EventDispatchDetails dispatch_details =
 321         DispatchEvent(mouse_pressed_handler_, &mouse_pressed_event);
 322     if (dispatch_details.dispatcher_destroyed)
 323       return true;
 324     return true;
 325   }
 326   DCHECK(!explicit_mouse_handler_);
 327
 328   bool hit_disabled_view = false;
 329   // Walk up the tree until we find a view that wants the mouse event.
 330   for (mouse_pressed_handler_ = GetEventHandlerForPoint(event.location());
 331        mouse_pressed_handler_ && (mouse_pressed_handler_ != this);
 332        mouse_pressed_handler_ = mouse_pressed_handler_->parent()) {
 333     DVLOG(1) << "OnMousePressed testing "
 334         << mouse_pressed_handler_->GetClassName();
 335     if (!mouse_pressed_handler_->enabled()) {
 336       // Disabled views should eat events instead of propagating them upwards.
 337       hit_disabled_view = true;
 338       break;
 339     }
 340
 341     // See if this view wants to handle the mouse press.
 342     ui::MouseEvent mouse_pressed_event(event, static_cast<View*>(this),
 343                                        mouse_pressed_handler_);
 344
 345     // Remove the double-click flag if the handler is different than the
 346     // one which got the first click part of the double-click.
 347     if (mouse_pressed_handler_ != last_click_handler_)
 348       mouse_pressed_event.set_flags(event.flags() & ~ui::EF_IS_DOUBLE_CLICK);
 349
 350     drag_info_.Reset();
 351     ui::EventDispatchDetails dispatch_details =
 352         DispatchEvent(mouse_pressed_handler_, &mouse_pressed_event);
 353     if (dispatch_details.dispatcher_destroyed)
 354       return mouse_pressed_event.handled();
 355
 356     // The view could have removed itself from the tree when handling
 357     // OnMousePressed().  In this case, the removal notification will have
 358     // reset mouse_pressed_handler_ to NULL out from under us.  Detect this
 359     // case and stop.  (See comments in view.h.)
 360     //
 361     // NOTE: Don't return true here, because we don't want the frame to
 362     // forward future events to us when there's no handler.
 363     if (!mouse_pressed_handler_)
 364       break;
 365
 366     // If the view handled the event, leave mouse_pressed_handler_ set and
 367     // return true, which will cause subsequent drag/release events to get
 368     // forwarded to that view.
 369     if (mouse_pressed_event.handled()) {
 370       last_click_handler_ = mouse_pressed_handler_;
 371       DVLOG(1) << "OnMousePressed handled by "
 372           << mouse_pressed_handler_->GetClassName();
 373       return true;
 374     }
 375   }
 376
 377   // Reset mouse_pressed_handler_ to indicate that no processing is occurring.
 378   mouse_pressed_handler_ = NULL;
 379
 380   // In the event that a double-click is not handled after traversing the
 381   // entire hierarchy (even as a single-click when sent to a different view),
 382   // it must be marked as handled to avoid anything happening from default
 383   // processing if it the first click-part was handled by us.
 384   if (last_click_handler_ && (event.flags() & ui::EF_IS_DOUBLE_CLICK))
 385     hit_disabled_view = true;
 386
 387   last_click_handler_ = NULL;
 388   return hit_disabled_view;
 389 }
 390
 391 bool RootView::OnMouseDragged(const ui::MouseEvent& event) {
 392   if (mouse_pressed_handler_) {
 393     SetMouseLocationAndFlags(event);
 394
 395     ui::MouseEvent mouse_event(event, static_cast<View*>(this),
 396                                mouse_pressed_handler_);
 397     ui::EventDispatchDetails dispatch_details =
 398         DispatchEvent(mouse_pressed_handler_, &mouse_event);
 399     if (dispatch_details.dispatcher_destroyed)
 400       return false;
 401   }
 402   return false;
 403 }
 404
 405 void RootView::OnMouseReleased(const ui::MouseEvent& event) {
 406   UpdateCursor(event);
 407
 408   if (mouse_pressed_handler_) {
 409     ui::MouseEvent mouse_released(event, static_cast<View*>(this),
 410                                   mouse_pressed_handler_);
 411     // We allow the view to delete us from the event dispatch callback. As such,
 412     // configure state such that we're done first, then call View.
 413     View* mouse_pressed_handler = mouse_pressed_handler_;
 414     SetMouseHandler(NULL);
 415     ui::EventDispatchDetails dispatch_details =
 416         DispatchEvent(mouse_pressed_handler, &mouse_released);
 417     if (dispatch_details.dispatcher_destroyed)
 418       return;
 419   }
 420 }
 421
 422 void RootView::OnMouseCaptureLost() {
 423   // TODO: this likely needs to reset touch handler too.
 424
 425   if (mouse_pressed_handler_ || gesture_handler_) {
 426     // Synthesize a release event for UpdateCursor.
 427     if (mouse_pressed_handler_) {
 428       gfx::Point last_point(last_mouse_event_x_, last_mouse_event_y_);
 429       ui::MouseEvent release_event(ui::ET_MOUSE_RELEASED,
 430                                    last_point, last_point,
 431                                    last_mouse_event_flags_,
 432                                    0);
 433       UpdateCursor(release_event);
 434     }
 435     // We allow the view to delete us from OnMouseCaptureLost. As such,
 436     // configure state such that we're done first, then call View.
 437     View* mouse_pressed_handler = mouse_pressed_handler_;
 438     View* gesture_handler = gesture_handler_;
 439     SetMouseHandler(NULL);
 440     if (mouse_pressed_handler)
 441       mouse_pressed_handler->OnMouseCaptureLost();
 442     else
 443       gesture_handler->OnMouseCaptureLost();
 444     // WARNING: we may have been deleted.
 445   }
 446 }
 447
 448 void RootView::OnMouseMoved(const ui::MouseEvent& event) {
 449   View* v = GetEventHandlerForPoint(event.location());
 450   // Find the first enabled view, or the existing move handler, whichever comes
 451   // first.  The check for the existing handler is because if a view becomes
 452   // disabled while handling moves, it's wrong to suddenly send ET_MOUSE_EXITED
 453   // and ET_MOUSE_ENTERED events, because the mouse hasn't actually exited yet.
 454   while (v && !v->enabled() && (v != mouse_move_handler_))
 455     v = v->parent();
 456   if (v && v != this) {
 457     if (v != mouse_move_handler_) {
 458       if (mouse_move_handler_ != NULL &&
 459           (!mouse_move_handler_->notify_enter_exit_on_child() ||
 460            !mouse_move_handler_->Contains(v))) {
 461         MouseEnterExitEvent exit(event, ui::ET_MOUSE_EXITED);
 462         exit.ConvertLocationToTarget(static_cast<View*>(this),
 463                                      mouse_move_handler_);
 464         ui::EventDispatchDetails dispatch_details =
 465             DispatchEvent(mouse_move_handler_, &exit);
 466         if (dispatch_details.dispatcher_destroyed)
 467           return;
 468         NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 469             mouse_move_handler_, v);
 470       }
 471       View* old_handler = mouse_move_handler_;
 472       mouse_move_handler_ = v;
 473       if (!mouse_move_handler_->notify_enter_exit_on_child() ||
 474           !mouse_move_handler_->Contains(old_handler)) {
 475         MouseEnterExitEvent entered(event, ui::ET_MOUSE_ENTERED);
 476         entered.ConvertLocationToTarget(static_cast<View*>(this),
 477                                         mouse_move_handler_);
 478         ui::EventDispatchDetails dispatch_details =
 479             DispatchEvent(mouse_move_handler_, &entered);
 480         if (dispatch_details.dispatcher_destroyed)
 481           return;
 482         NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_ENTERED,
 483             mouse_move_handler_, old_handler);
 484       }
 485     }
 486     ui::MouseEvent moved_event(event, static_cast<View*>(this),
 487                                mouse_move_handler_);
 488     mouse_move_handler_->OnMouseMoved(moved_event);
 489     // TODO(tdanderson): It may be possible to avoid setting the cursor twice
 490     //                   (once here and once from CompoundEventFilter) on a
 491     //                   mousemove. See crbug.com/351469.
 492     if (!(moved_event.flags() & ui::EF_IS_NON_CLIENT))
 493       widget_->SetCursor(mouse_move_handler_->GetCursor(moved_event));
 494   } else if (mouse_move_handler_ != NULL) {
 495     MouseEnterExitEvent exited(event, ui::ET_MOUSE_EXITED);
 496     ui::EventDispatchDetails dispatch_details =
 497         DispatchEvent(mouse_move_handler_, &exited);
 498     if (dispatch_details.dispatcher_destroyed)
 499       return;
 500     NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 501         mouse_move_handler_, v);
 502     // On Aura the non-client area extends slightly outside the root view for
 503     // some windows.  Let the non-client cursor handling code set the cursor
 504     // as we do above.
 505     if (!(event.flags() & ui::EF_IS_NON_CLIENT))
 506       widget_->SetCursor(gfx::kNullCursor);
 507     mouse_move_handler_ = NULL;
 508   }
 509 }
 510
 511 void RootView::OnMouseExited(const ui::MouseEvent& event) {
 512   if (mouse_move_handler_ != NULL) {
 513     MouseEnterExitEvent exited(event, ui::ET_MOUSE_EXITED);
 514     ui::EventDispatchDetails dispatch_details =
 515         DispatchEvent(mouse_move_handler_, &exited);
 516     if (dispatch_details.dispatcher_destroyed)
 517       return;
 518     NotifyEnterExitOfDescendant(event, ui::ET_MOUSE_EXITED,
 519         mouse_move_handler_, NULL);
 520     mouse_move_handler_ = NULL;
 521   }
 522 }
 523
 524 bool RootView::OnMouseWheel(const ui::MouseWheelEvent& event) {
 525   for (View* v = GetEventHandlerForPoint(event.location());
 526        v && v != this && !event.handled(); v = v->parent()) {
 527     ui::EventDispatchDetails dispatch_details =
 528         DispatchEvent(v, const_cast<ui::MouseWheelEvent*>(&event));
 529     if (dispatch_details.dispatcher_destroyed ||
 530         dispatch_details.target_destroyed) {
 531       return event.handled();
 532     }
 533   }
 534   return event.handled();
 535 }
 536
 537 void RootView::SetMouseHandler(View* new_mh) {
 538   // If we're clearing the mouse handler, clear explicit_mouse_handler_ as well.
 539   explicit_mouse_handler_ = (new_mh != NULL);
 540   mouse_pressed_handler_ = new_mh;
 541   gesture_handler_ = new_mh;
 542   scroll_gesture_handler_ = new_mh;
 543   drag_info_.Reset();
 544 }
 545
 546 void RootView::GetAccessibleState(ui::AXViewState* state) {
 547   state->name = widget_->widget_delegate()->GetAccessibleWindowTitle();
 548   state->role = widget_->widget_delegate()->GetAccessibleWindowRole();
 549 }
 550
 551 void RootView::UpdateParentLayer() {
 552   if (layer())
 553     ReparentLayer(gfx::Vector2d(GetMirroredX(), y()), widget_->GetLayer());
 554 }
 555
 556 ////////////////////////////////////////////////////////////////////////////////
 557 // RootView, protected:
 558
 559 void RootView::ViewHierarchyChanged(
 560     const ViewHierarchyChangedDetails& details) {
 561   widget_->ViewHierarchyChanged(details);
 562
 563   if (!details.is_add) {
 564     if (!explicit_mouse_handler_ && mouse_pressed_handler_ == details.child)
 565       mouse_pressed_handler_ = NULL;
 566     if (mouse_move_handler_ == details.child)
 567       mouse_move_handler_ = NULL;
 568     if (gesture_handler_ == details.child)
 569       gesture_handler_ = NULL;
 570     if (scroll_gesture_handler_ == details.child)
 571       scroll_gesture_handler_ = NULL;
 572     if (event_dispatch_target_ == details.child)
 573       event_dispatch_target_ = NULL;
 574     if (old_dispatch_target_ == details.child)
 575       old_dispatch_target_ = NULL;
 576   }
 577 }
 578
 579 void RootView::VisibilityChanged(View* /*starting_from*/, bool is_visible) {
 580   if (!is_visible) {
 581     // When the root view is being hidden (e.g. when widget is minimized)
 582     // handlers are reset, so that after it is reshown, events are not captured
 583     // by old handlers.
 584     explicit_mouse_handler_ = false;
 585     mouse_pressed_handler_ = NULL;
 586     mouse_move_handler_ = NULL;
 587     gesture_handler_ = NULL;
 588     scroll_gesture_handler_ = NULL;
 589     event_dispatch_target_ = NULL;
 590     old_dispatch_target_ = NULL;
 591   }
 592 }
 593
 594 void RootView::OnPaint(gfx::Canvas* canvas) {
 595   if (!layer() || !layer()->fills_bounds_opaquely())
 596     canvas->DrawColor(SK_ColorBLACK, SkXfermode::kClear_Mode);
 597
 598   View::OnPaint(canvas);
 599 }
 600
 601 gfx::Vector2d RootView::CalculateOffsetToAncestorWithLayer(
 602     ui::Layer** layer_parent) {
 603   gfx::Vector2d offset(View::CalculateOffsetToAncestorWithLayer(layer_parent));
 604   if (!layer() && layer_parent)
 605     *layer_parent = widget_->GetLayer();
 606   return offset;
 607 }
 608
 609 View::DragInfo* RootView::GetDragInfo() {
 610   return &drag_info_;
 611 }
 612
 613 ////////////////////////////////////////////////////////////////////////////////
 614 // RootView, private:
 615
 616 // Input -----------------------------------------------------------------------
 617
 618 void RootView::DispatchGestureEvent(ui::GestureEvent* event) {
 619   if (gesture_handler_) {
 620     // |gesture_handler_| (or |scroll_gesture_handler_|) can be deleted during
 621     // processing.
 622     View* handler = scroll_gesture_handler_ &&
 623         (event->IsScrollGestureEvent() || event->IsFlingScrollEvent())  ?
 624             scroll_gesture_handler_ : gesture_handler_;
 625     ui::GestureEvent handler_event(*event, static_cast<View*>(this), handler);
 626     ui::EventDispatchDetails dispatch_details =
 627         DispatchEvent(handler, &handler_event);
 628     if (dispatch_details.dispatcher_destroyed)
 629       return;
 630
 631     if (event->type() == ui::ET_GESTURE_END &&
 632         event->details().touch_points() <= 1) {
 633       // In case a drag was in progress, reset all the handlers. Otherwise, just
 634       // reset the gesture handler.
 635       if (gesture_handler_ == mouse_pressed_handler_)
 636         SetMouseHandler(NULL);
 637       else
 638         gesture_handler_ = NULL;
 639     }
 640
 641     if (scroll_gesture_handler_ &&
 642         (event->type() == ui::ET_GESTURE_SCROLL_END ||
 643          event->type() == ui::ET_SCROLL_FLING_START)) {
 644       scroll_gesture_handler_ = NULL;
 645     }
 646
 647     if (handler_event.stopped_propagation()) {
 648       event->StopPropagation();
 649       return;
 650     } else if (handler_event.handled()) {
 651       event->SetHandled();
 652       return;
 653     }
 654
 655     if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN &&
 656         !scroll_gesture_handler_) {
 657       // Some view started processing gesture events, however it does not
 658       // process scroll-gesture events. In such case, we allow the event to
 659       // bubble up, and install a different scroll-gesture handler different
 660       // from the default gesture handler.
 661       for (scroll_gesture_handler_ = gesture_handler_->parent();
 662           scroll_gesture_handler_ && scroll_gesture_handler_ != this;
 663           scroll_gesture_handler_ = scroll_gesture_handler_->parent()) {
 664         ui::GestureEvent gesture_event(*event, static_cast<View*>(this),
 665                                        scroll_gesture_handler_);
 666         ui::EventDispatchDetails dispatch_details =
 667             DispatchEvent(scroll_gesture_handler_, &gesture_event);
 668         if (gesture_event.stopped_propagation()) {
 669           event->StopPropagation();
 670           return;
 671         } else if (gesture_event.handled()) {
 672           event->SetHandled();
 673           return;
 674         } else if (dispatch_details.dispatcher_destroyed ||
 675                    dispatch_details.target_destroyed) {
 676           return;
 677         }
 678       }
 679       scroll_gesture_handler_ = NULL;
 680     }
 681
 682     return;
 683   }
 684
 685   // If there was no handler for a SCROLL_BEGIN event, then subsequent scroll
 686   // events are not dispatched to any views.
 687   switch (event->type()) {
 688     case ui::ET_GESTURE_SCROLL_UPDATE:
 689     case ui::ET_GESTURE_SCROLL_END:
 690     case ui::ET_SCROLL_FLING_START:
 691       return;
 692     default:
 693       break;
 694   }
 695
 696   View* gesture_handler = NULL;
 697   if (views::switches::IsRectBasedTargetingEnabled() &&
 698       !event->details().bounding_box().IsEmpty()) {
 699     // TODO(tdanderson): Pass in the bounding box to GetEventHandlerForRect()
 700     // once crbug.com/313392 is resolved.
 701     gfx::Rect touch_rect(event->details().bounding_box());
 702     touch_rect.set_origin(event->location());
 703     touch_rect.Offset(-touch_rect.width() / 2, -touch_rect.height() / 2);
 704     gesture_handler = GetEventHandlerForRect(touch_rect);
 705   } else {
 706     gesture_handler = GetEventHandlerForPoint(event->location());
 707   }
 708
 709   // Walk up the tree until we find a view that wants the gesture event.
 710   for (gesture_handler_ = gesture_handler;
 711        gesture_handler_ && (gesture_handler_ != this);
 712        gesture_handler_ = gesture_handler_->parent()) {
 713     if (!gesture_handler_->enabled()) {
 714       // Disabled views eat events but are treated as not handled.
 715       return;
 716     }
 717
 718     // See if this view wants to handle the Gesture.
 719     ui::GestureEvent gesture_event(*event, static_cast<View*>(this),
 720                                    gesture_handler_);
 721     ui::EventDispatchDetails dispatch_details =
 722         DispatchEvent(gesture_handler_, &gesture_event);
 723     if (dispatch_details.dispatcher_destroyed)
 724       return;
 725
 726     // The view could have removed itself from the tree when handling
 727     // OnGestureEvent(). So handle as per OnMousePressed. NB: we
 728     // assume that the RootView itself cannot be so removed.
 729     if (!gesture_handler_)
 730       return;
 731
 732     if (gesture_event.handled()) {
 733       if (gesture_event.type() == ui::ET_GESTURE_SCROLL_BEGIN)
 734         scroll_gesture_handler_ = gesture_handler_;
 735       if (gesture_event.stopped_propagation())
 736         event->StopPropagation();
 737       else
 738         event->SetHandled();
 739       // Last ui::ET_GESTURE_END should not set the gesture_handler_.
 740       if (gesture_event.type() == ui::ET_GESTURE_END &&
 741           event->details().touch_points() <= 1) {
 742         gesture_handler_ = NULL;
 743       }
 744       return;
 745     }
 746
 747     // The gesture event wasn't processed. Go up the view hierarchy and
 748     // dispatch the gesture event.
 749   }
 750
 751   gesture_handler_ = NULL;
 752 }
 753
 754 void RootView::UpdateCursor(const ui::MouseEvent& event) {
 755   if (!(event.flags() & ui::EF_IS_NON_CLIENT)) {
 756     View* v = GetEventHandlerForPoint(event.location());
 757     ui::MouseEvent me(event, static_cast<View*>(this), v);
 758     widget_->SetCursor(v->GetCursor(me));
 759   }
 760 }
 761
 762 void RootView::SetMouseLocationAndFlags(const ui::MouseEvent& event) {
 763   last_mouse_event_flags_ = event.flags();
 764   last_mouse_event_x_ = event.x();
 765   last_mouse_event_y_ = event.y();
 766 }
 767
 768 void RootView::NotifyEnterExitOfDescendant(const ui::MouseEvent& event,
 769                                            ui::EventType type,
 770                                            View* view,
 771                                            View* sibling) {
 772   for (View* p = view->parent(); p; p = p->parent()) {
 773     if (!p->notify_enter_exit_on_child())
 774       continue;
 775     if (sibling && p->Contains(sibling))
 776       break;
 777     // It is necessary to recreate the notify-event for each dispatch, since one
 778     // of the callbacks can mark the event as handled, and that would cause
 779     // incorrect event dispatch.
 780     MouseEnterExitEvent notify_event(event, type);
 781     ui::EventDispatchDetails dispatch_details = DispatchEvent(p, &notify_event);
 782     if (dispatch_details.dispatcher_destroyed ||
 783         dispatch_details.target_destroyed) {
 784       return;
 785     }
 786   }
 787 }
 788
 789 bool RootView::CanDispatchToTarget(ui::EventTarget* target) {
 790   return event_dispatch_target_ == target;
 791 }
 792
 793 ui::EventDispatchDetails RootView::PreDispatchEvent(ui::EventTarget* target,
 794                                                     ui::Event* event) {
 795   old_dispatch_target_ = event_dispatch_target_;
 796   event_dispatch_target_ = static_cast<View*>(target);
 797   return DispatchDetails();
 798 }
 799
 800 ui::EventDispatchDetails RootView::PostDispatchEvent(ui::EventTarget* target,
 801                                                      const ui::Event& event) {
 802   DispatchDetails details;
 803   if (target != event_dispatch_target_)
 804     details.target_destroyed = true;
 805
 806   event_dispatch_target_ = old_dispatch_target_;
 807   old_dispatch_target_ = NULL;
 808
 809 #ifndef NDEBUG
 810   DCHECK(!event_dispatch_target_ || Contains(event_dispatch_target_));
 811 #endif
 812
 813   return details;
 814 }
 815
 816 }  // namespace internal
 817 }  // namespace views