ui/events/event_dispatcher_unittest.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/events/event_dispatcher.h"
   6
   7 #include "testing/gtest/include/gtest/gtest.h"
   8 #include "ui/events/event.h"
   9 #include "ui/events/event_dispatcher.h"
  10 #include "ui/events/event_target.h"
  11 #include "ui/events/event_target_iterator.h"
  12 #include "ui/events/event_utils.h"
  13
  14 namespace ui {
  15
  16 namespace {
  17
  18 class TestTarget : public EventTarget {
  19  public:
  20   TestTarget() : parent_(NULL), valid_(true) {}
  21   ~TestTarget() override {}
  22
  23   void set_parent(TestTarget* parent) { parent_ = parent; }
  24
  25   bool valid() const { return valid_; }
  26   void set_valid(bool valid) { valid_ = valid; }
  27
  28   void AddHandlerId(int id) {
  29     handler_list_.push_back(id);
  30   }
  31
  32   const std::vector<int>& handler_list() const { return handler_list_; }
  33
  34   void Reset() {
  35     handler_list_.clear();
  36     valid_ = true;
  37   }
  38
  39  private:
  40   // Overridden from EventTarget:
  41   bool CanAcceptEvent(const ui::Event& event) override { return true; }
  42
  43   EventTarget* GetParentTarget() override { return parent_; }
  44
  45   scoped_ptr<EventTargetIterator> GetChildIterator() const override {
  46     return nullptr;
  47   }
  48
  49   EventTargeter* GetEventTargeter() override { return NULL; }
  50
  51   TestTarget* parent_;
  52   std::vector<int> handler_list_;
  53   bool valid_;
  54
  55   DISALLOW_COPY_AND_ASSIGN(TestTarget);
  56 };
  57
  58 class TestEventHandler : public EventHandler {
  59  public:
  60   TestEventHandler(int id)
  61       : id_(id),
  62         event_result_(ER_UNHANDLED),
  63         expect_pre_target_(false),
  64         expect_post_target_(false),
  65         received_pre_target_(false) {
  66   }
  67
  68   ~TestEventHandler() override {}
  69
  70   virtual void ReceivedEvent(Event* event) {
  71     static_cast<TestTarget*>(event->target())->AddHandlerId(id_);
  72     if (event->phase() == ui::EP_POSTTARGET) {
  73       EXPECT_TRUE(expect_post_target_);
  74       if (expect_pre_target_)
  75         EXPECT_TRUE(received_pre_target_);
  76     } else if (event->phase() == ui::EP_PRETARGET) {
  77       EXPECT_TRUE(expect_pre_target_);
  78       received_pre_target_ = true;
  79     } else {
  80       NOTREACHED();
  81     }
  82   }
  83
  84   void set_event_result(EventResult result) { event_result_ = result; }
  85
  86   void set_expect_pre_target(bool expect) { expect_pre_target_ = expect; }
  87   void set_expect_post_target(bool expect) { expect_post_target_ = expect; }
  88
  89  private:
  90   // Overridden from EventHandler:
  91   void OnEvent(Event* event) override {
  92     ui::EventHandler::OnEvent(event);
  93     ReceivedEvent(event);
  94     SetStatusOnEvent(event);
  95   }
  96
  97   void SetStatusOnEvent(Event* event) {
  98     if (event_result_ & ui::ER_CONSUMED)
  99       event->StopPropagation();
 100     if (event_result_ & ui::ER_HANDLED)
 101       event->SetHandled();
 102   }
 103
 104   int id_;
 105   EventResult event_result_;
 106   bool expect_pre_target_;
 107   bool expect_post_target_;
 108   bool received_pre_target_;
 109
 110   DISALLOW_COPY_AND_ASSIGN(TestEventHandler);
 111 };
 112
 113 class NonCancelableEvent : public Event {
 114  public:
 115   NonCancelableEvent()
 116       : Event(ui::ET_CANCEL_MODE, ui::EventTimeForNow(), 0) {
 117     set_cancelable(false);
 118   }
 119
 120   ~NonCancelableEvent() override {}
 121
 122  private:
 123   DISALLOW_COPY_AND_ASSIGN(NonCancelableEvent);
 124 };
 125
 126 // Destroys the dispatcher-delegate when it receives any event.
 127 class EventHandlerDestroyDispatcherDelegate : public TestEventHandler {
 128  public:
 129   EventHandlerDestroyDispatcherDelegate(EventDispatcherDelegate* delegate,
 130                                         int id)
 131       : TestEventHandler(id),
 132         dispatcher_delegate_(delegate) {
 133   }
 134
 135   ~EventHandlerDestroyDispatcherDelegate() override {}
 136
 137  private:
 138   void ReceivedEvent(Event* event) override {
 139     TestEventHandler::ReceivedEvent(event);
 140     delete dispatcher_delegate_;
 141   }
 142
 143   EventDispatcherDelegate* dispatcher_delegate_;
 144
 145   DISALLOW_COPY_AND_ASSIGN(EventHandlerDestroyDispatcherDelegate);
 146 };
 147
 148 // Invalidates the target when it receives any event.
 149 class InvalidateTargetEventHandler : public TestEventHandler {
 150  public:
 151   explicit InvalidateTargetEventHandler(int id) : TestEventHandler(id) {}
 152   ~InvalidateTargetEventHandler() override {}
 153
 154  private:
 155   void ReceivedEvent(Event* event) override {
 156    TestEventHandler::ReceivedEvent(event);
 157    TestTarget* target = static_cast<TestTarget*>(event->target());
 158    target->set_valid(false);
 159   }
 160
 161   DISALLOW_COPY_AND_ASSIGN(InvalidateTargetEventHandler);
 162 };
 163
 164 // Destroys a second event handler when this handler gets an event.
 165 // Optionally also destroys the dispatcher.
 166 class EventHandlerDestroyer : public TestEventHandler {
 167  public:
 168   EventHandlerDestroyer(int id, EventHandler* destroy)
 169       : TestEventHandler(id),
 170         to_destroy_(destroy),
 171         dispatcher_delegate_(NULL) {
 172   }
 173
 174   ~EventHandlerDestroyer() override { CHECK(!to_destroy_); }
 175
 176   void set_dispatcher_delegate(EventDispatcherDelegate* dispatcher_delegate) {
 177     dispatcher_delegate_ = dispatcher_delegate;
 178   }
 179
 180  private:
 181   void ReceivedEvent(Event* event) override {
 182     TestEventHandler::ReceivedEvent(event);
 183     delete to_destroy_;
 184     to_destroy_ = NULL;
 185
 186     if (dispatcher_delegate_) {
 187       delete dispatcher_delegate_;
 188       dispatcher_delegate_ = NULL;
 189     }
 190   }
 191
 192   EventHandler* to_destroy_;
 193   EventDispatcherDelegate* dispatcher_delegate_;
 194
 195   DISALLOW_COPY_AND_ASSIGN(EventHandlerDestroyer);
 196 };
 197
 198 class TestEventDispatcher : public EventDispatcherDelegate {
 199  public:
 200   TestEventDispatcher() {}
 201
 202   ~TestEventDispatcher() override {}
 203
 204   EventDispatchDetails ProcessEvent(EventTarget* target, Event* event) {
 205     return DispatchEvent(target, event);
 206   }
 207
 208  private:
 209   // Overridden from EventDispatcherDelegate:
 210   bool CanDispatchToTarget(EventTarget* target) override {
 211     TestTarget* test_target = static_cast<TestTarget*>(target);
 212     return test_target->valid();
 213   }
 214
 215   DISALLOW_COPY_AND_ASSIGN(TestEventDispatcher);
 216 };
 217
 218 }  // namespace
 219
 220 TEST(EventDispatcherTest, EventDispatchOrder) {
 221   TestEventDispatcher dispatcher;
 222   TestTarget parent, child;
 223   TestEventHandler h1(1), h2(2), h3(3), h4(4);
 224   TestEventHandler h5(5), h6(6), h7(7), h8(8);
 225
 226   child.set_parent(&parent);
 227
 228   parent.AddPreTargetHandler(&h1);
 229   parent.AddPreTargetHandler(&h2);
 230
 231   child.AddPreTargetHandler(&h3);
 232   child.AddPreTargetHandler(&h4);
 233
 234   h1.set_expect_pre_target(true);
 235   h2.set_expect_pre_target(true);
 236   h3.set_expect_pre_target(true);
 237   h4.set_expect_pre_target(true);
 238
 239   child.AddPostTargetHandler(&h5);
 240   child.AddPostTargetHandler(&h6);
 241
 242   parent.AddPostTargetHandler(&h7);
 243   parent.AddPostTargetHandler(&h8);
 244
 245   h5.set_expect_post_target(true);
 246   h6.set_expect_post_target(true);
 247   h7.set_expect_post_target(true);
 248   h8.set_expect_post_target(true);
 249
 250   MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 251                    ui::EventTimeForNow(), 0, 0);
 252   Event::DispatcherApi event_mod(&mouse);
 253   dispatcher.ProcessEvent(&child, &mouse);
 254   EXPECT_FALSE(mouse.stopped_propagation());
 255   EXPECT_FALSE(mouse.handled());
 256
 257   {
 258     int expected[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
 259     EXPECT_EQ(
 260         std::vector<int>(expected, expected + sizeof(expected) / sizeof(int)),
 261         child.handler_list());
 262   }
 263
 264   child.Reset();
 265   event_mod.set_phase(EP_PREDISPATCH);
 266   event_mod.set_result(ER_UNHANDLED);
 267
 268   h1.set_event_result(ER_HANDLED);
 269   dispatcher.ProcessEvent(&child, &mouse);
 270   EXPECT_EQ(EP_POSTDISPATCH, mouse.phase());
 271   EXPECT_FALSE(mouse.stopped_propagation());
 272   EXPECT_TRUE(mouse.handled());
 273   {
 274     // |h1| marks the event as handled. So only the pre-target handlers should
 275     // receive the event.
 276     int expected[] = { 1, 2, 3, 4 };
 277     EXPECT_EQ(
 278         std::vector<int>(expected, expected + sizeof(expected) / sizeof(int)),
 279         child.handler_list());
 280   }
 281
 282   child.Reset();
 283   event_mod.set_phase(EP_PREDISPATCH);
 284   event_mod.set_result(ER_UNHANDLED);
 285
 286   int nexpected[] = { 1, 2, 3, 4, 5 };
 287   h1.set_event_result(ER_UNHANDLED);
 288   h5.set_event_result(ER_CONSUMED);
 289   dispatcher.ProcessEvent(&child, &mouse);
 290   EXPECT_EQ(EP_POSTDISPATCH, mouse.phase());
 291   EXPECT_TRUE(mouse.stopped_propagation());
 292   EXPECT_TRUE(mouse.handled());
 293   EXPECT_EQ(
 294       std::vector<int>(nexpected, nexpected + sizeof(nexpected) / sizeof(int)),
 295       child.handler_list());
 296
 297   child.Reset();
 298   event_mod.set_phase(EP_PREDISPATCH);
 299   event_mod.set_result(ER_UNHANDLED);
 300
 301   int exp[] = { 1 };
 302   h1.set_event_result(ER_CONSUMED);
 303   dispatcher.ProcessEvent(&child, &mouse);
 304   EXPECT_EQ(EP_POSTDISPATCH, mouse.phase());
 305   EXPECT_TRUE(mouse.stopped_propagation());
 306   EXPECT_TRUE(mouse.handled());
 307   EXPECT_EQ(
 308       std::vector<int>(exp, exp + sizeof(exp) / sizeof(int)),
 309       child.handler_list());
 310 }
 311
 312 // Tests that the event-phases are correct.
 313 TEST(EventDispatcherTest, EventDispatchPhase) {
 314   TestEventDispatcher dispatcher;
 315   TestTarget target;
 316
 317   TestEventHandler handler(11);
 318
 319   target.AddPreTargetHandler(&handler);
 320   target.AddPostTargetHandler(&handler);
 321   handler.set_expect_pre_target(true);
 322   handler.set_expect_post_target(true);
 323
 324   MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 325                    ui::EventTimeForNow(), 0, 0);
 326   Event::DispatcherApi event_mod(&mouse);
 327   dispatcher.ProcessEvent(&target, &mouse);
 328   EXPECT_EQ(ER_UNHANDLED, mouse.result());
 329
 330   int handlers[] = { 11, 11 };
 331   EXPECT_EQ(
 332       std::vector<int>(handlers, handlers + sizeof(handlers) / sizeof(int)),
 333       target.handler_list());
 334 }
 335
 336 // Tests that if the dispatcher is destroyed in the middle of pre or post-target
 337 // dispatching events, it doesn't cause a crash.
 338 TEST(EventDispatcherTest, EventDispatcherDestroyedDuringDispatch) {
 339   // Test for pre-target first.
 340   {
 341     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 342     TestTarget target;
 343     EventHandlerDestroyDispatcherDelegate handler(dispatcher, 5);
 344     TestEventHandler h1(1), h2(2);
 345
 346     target.AddPreTargetHandler(&h1);
 347     target.AddPreTargetHandler(&handler);
 348     target.AddPreTargetHandler(&h2);
 349
 350     h1.set_expect_pre_target(true);
 351     handler.set_expect_pre_target(true);
 352     // |h2| should not receive any events at all since |handler| will have
 353     // destroyed the dispatcher.
 354     h2.set_expect_pre_target(false);
 355
 356     MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 357                      ui::EventTimeForNow(), 0, 0);
 358     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &mouse);
 359     EXPECT_TRUE(details.dispatcher_destroyed);
 360     EXPECT_EQ(ER_CONSUMED, mouse.result());
 361     EXPECT_EQ(2U, target.handler_list().size());
 362     EXPECT_EQ(1, target.handler_list()[0]);
 363     EXPECT_EQ(5, target.handler_list()[1]);
 364   }
 365
 366   // Test for non-cancelable event.
 367   {
 368     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 369     TestTarget target;
 370     EventHandlerDestroyDispatcherDelegate handler(dispatcher, 5);
 371     TestEventHandler h1(1), h2(2);
 372
 373     target.AddPreTargetHandler(&h1);
 374     target.AddPreTargetHandler(&handler);
 375     target.AddPreTargetHandler(&h2);
 376
 377     h1.set_expect_pre_target(true);
 378     handler.set_expect_pre_target(true);
 379     // |h2| should not receive any events at all since |handler| will have
 380     // destroyed the dispatcher.
 381     h2.set_expect_pre_target(false);
 382
 383     NonCancelableEvent event;
 384     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &event);
 385     EXPECT_TRUE(details.dispatcher_destroyed);
 386     EXPECT_EQ(2U, target.handler_list().size());
 387     EXPECT_EQ(1, target.handler_list()[0]);
 388     EXPECT_EQ(5, target.handler_list()[1]);
 389   }
 390
 391   // Now test for post-target.
 392   {
 393     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 394     TestTarget target;
 395     EventHandlerDestroyDispatcherDelegate handler(dispatcher, 5);
 396     TestEventHandler h1(1), h2(2);
 397
 398     target.AddPostTargetHandler(&h1);
 399     target.AddPostTargetHandler(&handler);
 400     target.AddPostTargetHandler(&h2);
 401
 402     h1.set_expect_post_target(true);
 403     handler.set_expect_post_target(true);
 404     // |h2| should not receive any events at all since |handler| will have
 405     // destroyed the dispatcher.
 406     h2.set_expect_post_target(false);
 407
 408     MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 409                      ui::EventTimeForNow(), 0, 0);
 410     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &mouse);
 411     EXPECT_TRUE(details.dispatcher_destroyed);
 412     EXPECT_EQ(ER_CONSUMED, mouse.result());
 413     EXPECT_EQ(2U, target.handler_list().size());
 414     EXPECT_EQ(1, target.handler_list()[0]);
 415     EXPECT_EQ(5, target.handler_list()[1]);
 416   }
 417
 418   // Test for non-cancelable event.
 419   {
 420     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 421     TestTarget target;
 422     EventHandlerDestroyDispatcherDelegate handler(dispatcher, 5);
 423     TestEventHandler h1(1), h2(2);
 424
 425     target.AddPostTargetHandler(&h1);
 426     target.AddPostTargetHandler(&handler);
 427     target.AddPostTargetHandler(&h2);
 428
 429     h1.set_expect_post_target(true);
 430     handler.set_expect_post_target(true);
 431     // |h2| should not receive any events at all since |handler| will have
 432     // destroyed the dispatcher.
 433     h2.set_expect_post_target(false);
 434
 435     NonCancelableEvent event;
 436     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &event);
 437     EXPECT_TRUE(details.dispatcher_destroyed);
 438     EXPECT_EQ(2U, target.handler_list().size());
 439     EXPECT_EQ(1, target.handler_list()[0]);
 440     EXPECT_EQ(5, target.handler_list()[1]);
 441   }
 442 }
 443
 444 // Tests that a target becoming invalid in the middle of pre- or post-target
 445 // event processing aborts processing.
 446 TEST(EventDispatcherTest, EventDispatcherInvalidateTarget) {
 447   TestEventDispatcher dispatcher;
 448   TestTarget target;
 449   TestEventHandler h1(1);
 450   InvalidateTargetEventHandler invalidate_handler(2);
 451   TestEventHandler h3(3);
 452
 453   target.AddPreTargetHandler(&h1);
 454   target.AddPreTargetHandler(&invalidate_handler);
 455   target.AddPreTargetHandler(&h3);
 456
 457   h1.set_expect_pre_target(true);
 458   invalidate_handler.set_expect_pre_target(true);
 459   // |h3| should not receive events as the target will be invalidated.
 460   h3.set_expect_pre_target(false);
 461
 462   MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 463                    ui::EventTimeForNow(), 0, 0);
 464   EventDispatchDetails details = dispatcher.ProcessEvent(&target, &mouse);
 465   EXPECT_FALSE(details.dispatcher_destroyed);
 466   EXPECT_TRUE(details.target_destroyed);
 467   EXPECT_FALSE(target.valid());
 468   EXPECT_TRUE(mouse.stopped_propagation());
 469   EXPECT_EQ(2U, target.handler_list().size());
 470   EXPECT_EQ(1, target.handler_list()[0]);
 471   EXPECT_EQ(2, target.handler_list()[1]);
 472
 473   // Test for non-cancelable event.
 474   target.Reset();
 475   NonCancelableEvent event;
 476   details = dispatcher.ProcessEvent(&target, &event);
 477   EXPECT_FALSE(details.dispatcher_destroyed);
 478   EXPECT_TRUE(details.target_destroyed);
 479   EXPECT_FALSE(target.valid());
 480   EXPECT_EQ(2U, target.handler_list().size());
 481   EXPECT_EQ(1, target.handler_list()[0]);
 482   EXPECT_EQ(2, target.handler_list()[1]);
 483 }
 484
 485 // Tests that if an event-handler gets destroyed during event-dispatch, it does
 486 // not cause a crash.
 487 TEST(EventDispatcherTest, EventHandlerDestroyedDuringDispatch) {
 488   {
 489     TestEventDispatcher dispatcher;
 490     TestTarget target;
 491     TestEventHandler h1(1);
 492     TestEventHandler* h3 = new TestEventHandler(3);
 493     EventHandlerDestroyer handle_destroyer(2, h3);
 494
 495     target.AddPreTargetHandler(&h1);
 496     target.AddPreTargetHandler(&handle_destroyer);
 497     target.AddPreTargetHandler(h3);
 498
 499     h1.set_expect_pre_target(true);
 500     handle_destroyer.set_expect_pre_target(true);
 501     // |h3| should not receive events since |handle_destroyer| will have
 502     // destroyed it.
 503     h3->set_expect_pre_target(false);
 504
 505     MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 506                      ui::EventTimeForNow(), 0, 0);
 507     EventDispatchDetails details = dispatcher.ProcessEvent(&target, &mouse);
 508     EXPECT_FALSE(details.dispatcher_destroyed);
 509     EXPECT_FALSE(details.target_destroyed);
 510     EXPECT_FALSE(mouse.stopped_propagation());
 511     EXPECT_EQ(2U, target.handler_list().size());
 512     EXPECT_EQ(1, target.handler_list()[0]);
 513     EXPECT_EQ(2, target.handler_list()[1]);
 514   }
 515
 516   // Test for non-cancelable events.
 517   {
 518     TestEventDispatcher dispatcher;
 519     TestTarget target;
 520     TestEventHandler h1(1);
 521     TestEventHandler* h3 = new TestEventHandler(3);
 522     EventHandlerDestroyer handle_destroyer(2, h3);
 523
 524     target.AddPreTargetHandler(&h1);
 525     target.AddPreTargetHandler(&handle_destroyer);
 526     target.AddPreTargetHandler(h3);
 527
 528     h1.set_expect_pre_target(true);
 529     handle_destroyer.set_expect_pre_target(true);
 530     h3->set_expect_pre_target(false);
 531
 532     NonCancelableEvent event;
 533     EventDispatchDetails details = dispatcher.ProcessEvent(&target, &event);
 534     EXPECT_FALSE(details.dispatcher_destroyed);
 535     EXPECT_FALSE(details.target_destroyed);
 536     EXPECT_EQ(2U, target.handler_list().size());
 537     EXPECT_EQ(1, target.handler_list()[0]);
 538     EXPECT_EQ(2, target.handler_list()[1]);
 539   }
 540 }
 541
 542 // Tests that things work correctly if an event-handler destroys both the
 543 // dispatcher and a handler.
 544 TEST(EventDispatcherTest, EventHandlerAndDispatcherDestroyedDuringDispatch) {
 545   {
 546     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 547     TestTarget target;
 548     TestEventHandler h1(1);
 549     TestEventHandler* h3 = new TestEventHandler(3);
 550     EventHandlerDestroyer destroyer(2, h3);
 551
 552     target.AddPreTargetHandler(&h1);
 553     target.AddPreTargetHandler(&destroyer);
 554     target.AddPreTargetHandler(h3);
 555
 556     h1.set_expect_pre_target(true);
 557     destroyer.set_expect_pre_target(true);
 558     destroyer.set_dispatcher_delegate(dispatcher);
 559     // |h3| should not receive events since |destroyer| will have destroyed
 560     // it.
 561     h3->set_expect_pre_target(false);
 562
 563     MouseEvent mouse(ui::ET_MOUSE_MOVED, gfx::Point(3, 4), gfx::Point(3, 4),
 564                      ui::EventTimeForNow(), 0, 0);
 565     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &mouse);
 566     EXPECT_TRUE(details.dispatcher_destroyed);
 567     EXPECT_TRUE(mouse.stopped_propagation());
 568     EXPECT_EQ(2U, target.handler_list().size());
 569     EXPECT_EQ(1, target.handler_list()[0]);
 570     EXPECT_EQ(2, target.handler_list()[1]);
 571   }
 572
 573   // Test for non-cancelable events.
 574   {
 575     TestEventDispatcher* dispatcher = new TestEventDispatcher();
 576     TestTarget target;
 577     TestEventHandler h1(1);
 578     TestEventHandler* h3 = new TestEventHandler(3);
 579     EventHandlerDestroyer destroyer(2, h3);
 580
 581     target.AddPreTargetHandler(&h1);
 582     target.AddPreTargetHandler(&destroyer);
 583     target.AddPreTargetHandler(h3);
 584
 585     h1.set_expect_pre_target(true);
 586     destroyer.set_expect_pre_target(true);
 587     destroyer.set_dispatcher_delegate(dispatcher);
 588     // |h3| should not receive events since |destroyer| will have destroyed
 589     // it.
 590     h3->set_expect_pre_target(false);
 591
 592     NonCancelableEvent event;
 593     EventDispatchDetails details = dispatcher->ProcessEvent(&target, &event);
 594     EXPECT_TRUE(details.dispatcher_destroyed);
 595     EXPECT_EQ(2U, target.handler_list().size());
 596     EXPECT_EQ(1, target.handler_list()[0]);
 597     EXPECT_EQ(2, target.handler_list()[1]);
 598   }
 599 }
 600
 601 }  // namespace ui