ui/events/platform/platform_event_source_unittest.cc

   1 // Copyright 2014 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/platform/platform_event_source.h"
   6
   7 #include "base/bind.h"
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/memory/scoped_vector.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "base/run_loop.h"
  12 #include "testing/gtest/include/gtest/gtest.h"
  13 #include "ui/events/platform/platform_event_dispatcher.h"
  14 #include "ui/events/platform/platform_event_observer.h"
  15 #include "ui/events/platform/scoped_event_dispatcher.h"
  16
  17 namespace ui {
  18
  19 namespace {
  20
  21 scoped_ptr<PlatformEvent> CreatePlatformEvent() {
  22   scoped_ptr<PlatformEvent> event(new PlatformEvent());
  23   memset(event.get(), 0, sizeof(PlatformEvent));
  24   return event.Pass();
  25 }
  26
  27 template <typename T>
  28 void DestroyScopedPtr(scoped_ptr<T> object) {}
  29
  30 void RemoveDispatcher(PlatformEventDispatcher* dispatcher) {
  31   PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(dispatcher);
  32 }
  33
  34 void RemoveDispatchers(PlatformEventDispatcher* first,
  35                        PlatformEventDispatcher* second) {
  36   PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(first);
  37   PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(second);
  38 }
  39
  40 void AddDispatcher(PlatformEventDispatcher* dispatcher) {
  41   PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(dispatcher);
  42 }
  43
  44 }  // namespace
  45
  46 class TestPlatformEventSource : public PlatformEventSource {
  47  public:
  48   TestPlatformEventSource()
  49       : stop_stream_(false) {
  50   }
  51   ~TestPlatformEventSource() override {}
  52
  53   uint32_t Dispatch(const PlatformEvent& event) { return DispatchEvent(event); }
  54
  55   // Dispatches the stream of events, and returns the number of events that are
  56   // dispatched before it is requested to stop.
  57   size_t DispatchEventStream(const ScopedVector<PlatformEvent>& events) {
  58     stop_stream_ = false;
  59     for (size_t count = 0; count < events.size(); ++count) {
  60       DispatchEvent(*events[count]);
  61       if (stop_stream_)
  62         return count + 1;
  63     }
  64     return events.size();
  65   }
  66
  67   // PlatformEventSource:
  68   void StopCurrentEventStream() override { stop_stream_ = true; }
  69
  70  private:
  71   bool stop_stream_;
  72   DISALLOW_COPY_AND_ASSIGN(TestPlatformEventSource);
  73 };
  74
  75 class TestPlatformEventDispatcher : public PlatformEventDispatcher {
  76  public:
  77   TestPlatformEventDispatcher(int id, std::vector<int>* list)
  78       : id_(id),
  79         list_(list),
  80         post_dispatch_action_(POST_DISPATCH_NONE) {
  81     PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(this);
  82   }
  83   ~TestPlatformEventDispatcher() override {
  84     PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(this);
  85   }
  86
  87   void set_post_dispatch_action(uint32_t action) {
  88     post_dispatch_action_ = action;
  89   }
  90
  91  protected:
  92   // PlatformEventDispatcher:
  93   bool CanDispatchEvent(const PlatformEvent& event) override { return true; }
  94
  95   uint32_t DispatchEvent(const PlatformEvent& event) override {
  96     list_->push_back(id_);
  97     return post_dispatch_action_;
  98   }
  99
 100  private:
 101   int id_;
 102   std::vector<int>* list_;
 103   uint32_t post_dispatch_action_;
 104
 105   DISALLOW_COPY_AND_ASSIGN(TestPlatformEventDispatcher);
 106 };
 107
 108 class TestPlatformEventObserver : public PlatformEventObserver {
 109  public:
 110   TestPlatformEventObserver(int id, std::vector<int>* list)
 111       : id_(id), list_(list) {
 112     PlatformEventSource::GetInstance()->AddPlatformEventObserver(this);
 113   }
 114   ~TestPlatformEventObserver() override {
 115     PlatformEventSource::GetInstance()->RemovePlatformEventObserver(this);
 116   }
 117
 118  protected:
 119   // PlatformEventObserver:
 120   void WillProcessEvent(const PlatformEvent& event) override {
 121     list_->push_back(id_);
 122   }
 123
 124   void DidProcessEvent(const PlatformEvent& event) override {}
 125
 126  private:
 127   int id_;
 128   std::vector<int>* list_;
 129
 130   DISALLOW_COPY_AND_ASSIGN(TestPlatformEventObserver);
 131 };
 132
 133 class PlatformEventTest : public testing::Test {
 134  public:
 135   PlatformEventTest() {}
 136   ~PlatformEventTest() override {}
 137
 138   TestPlatformEventSource* source() { return source_.get(); }
 139
 140  protected:
 141   // testing::Test:
 142   void SetUp() override { source_.reset(new TestPlatformEventSource()); }
 143
 144  private:
 145   scoped_ptr<TestPlatformEventSource> source_;
 146
 147   DISALLOW_COPY_AND_ASSIGN(PlatformEventTest);
 148 };
 149
 150 // Tests that a dispatcher receives an event.
 151 TEST_F(PlatformEventTest, DispatcherBasic) {
 152   std::vector<int> list_dispatcher;
 153   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 154   source()->Dispatch(*event);
 155   EXPECT_EQ(0u, list_dispatcher.size());
 156   {
 157     TestPlatformEventDispatcher dispatcher(1, &list_dispatcher);
 158
 159     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 160     source()->Dispatch(*event);
 161     ASSERT_EQ(1u, list_dispatcher.size());
 162     EXPECT_EQ(1, list_dispatcher[0]);
 163   }
 164
 165   list_dispatcher.clear();
 166   event = CreatePlatformEvent();
 167   source()->Dispatch(*event);
 168   EXPECT_EQ(0u, list_dispatcher.size());
 169 }
 170
 171 // Tests that dispatchers receive events in the correct order.
 172 TEST_F(PlatformEventTest, DispatcherOrder) {
 173   std::vector<int> list_dispatcher;
 174   int sequence[] = {21, 3, 6, 45};
 175   ScopedVector<TestPlatformEventDispatcher> dispatchers;
 176   for (size_t i = 0; i < arraysize(sequence); ++i) {
 177     dispatchers.push_back(
 178         new TestPlatformEventDispatcher(sequence[i], &list_dispatcher));
 179   }
 180   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 181   source()->Dispatch(*event);
 182   ASSERT_EQ(arraysize(sequence), list_dispatcher.size());
 183   EXPECT_EQ(std::vector<int>(sequence, sequence + arraysize(sequence)),
 184             list_dispatcher);
 185 }
 186
 187 // Tests that if a dispatcher consumes the event, the subsequent dispatchers do
 188 // not receive the event.
 189 TEST_F(PlatformEventTest, DispatcherConsumesEventToStopDispatch) {
 190   std::vector<int> list_dispatcher;
 191   TestPlatformEventDispatcher first(12, &list_dispatcher);
 192   TestPlatformEventDispatcher second(23, &list_dispatcher);
 193
 194   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 195   source()->Dispatch(*event);
 196   ASSERT_EQ(2u, list_dispatcher.size());
 197   EXPECT_EQ(12, list_dispatcher[0]);
 198   EXPECT_EQ(23, list_dispatcher[1]);
 199   list_dispatcher.clear();
 200
 201   first.set_post_dispatch_action(POST_DISPATCH_STOP_PROPAGATION);
 202   event = CreatePlatformEvent();
 203   source()->Dispatch(*event);
 204   ASSERT_EQ(1u, list_dispatcher.size());
 205   EXPECT_EQ(12, list_dispatcher[0]);
 206 }
 207
 208 // Tests that observers receive events.
 209 TEST_F(PlatformEventTest, ObserverBasic) {
 210   std::vector<int> list_observer;
 211   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 212   source()->Dispatch(*event);
 213   EXPECT_EQ(0u, list_observer.size());
 214   {
 215     TestPlatformEventObserver observer(31, &list_observer);
 216
 217     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 218     source()->Dispatch(*event);
 219     ASSERT_EQ(1u, list_observer.size());
 220     EXPECT_EQ(31, list_observer[0]);
 221   }
 222
 223   list_observer.clear();
 224   event = CreatePlatformEvent();
 225   source()->Dispatch(*event);
 226   EXPECT_EQ(0u, list_observer.size());
 227 }
 228
 229 // Tests that observers receive events in the correct order.
 230 TEST_F(PlatformEventTest, ObserverOrder) {
 231   std::vector<int> list_observer;
 232   const int sequence[] = {21, 3, 6, 45};
 233   ScopedVector<TestPlatformEventObserver> observers;
 234   for (size_t i = 0; i < arraysize(sequence); ++i) {
 235     observers.push_back(
 236         new TestPlatformEventObserver(sequence[i], &list_observer));
 237   }
 238   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 239   source()->Dispatch(*event);
 240   ASSERT_EQ(arraysize(sequence), list_observer.size());
 241   EXPECT_EQ(std::vector<int>(sequence, sequence + arraysize(sequence)),
 242             list_observer);
 243 }
 244
 245 // Tests that observers and dispatchers receive events in the correct order.
 246 TEST_F(PlatformEventTest, DispatcherAndObserverOrder) {
 247   std::vector<int> list;
 248   TestPlatformEventDispatcher first_d(12, &list);
 249   TestPlatformEventObserver first_o(10, &list);
 250   TestPlatformEventDispatcher second_d(23, &list);
 251   TestPlatformEventObserver second_o(20, &list);
 252   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 253   source()->Dispatch(*event);
 254   const int expected[] = {10, 20, 12, 23};
 255   EXPECT_EQ(std::vector<int>(expected, expected + arraysize(expected)), list);
 256 }
 257
 258 // Tests that an overridden dispatcher receives events before the default
 259 // dispatchers.
 260 TEST_F(PlatformEventTest, OverriddenDispatcherBasic) {
 261   std::vector<int> list;
 262   TestPlatformEventDispatcher dispatcher(10, &list);
 263   TestPlatformEventObserver observer(15, &list);
 264   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 265   source()->Dispatch(*event);
 266   ASSERT_EQ(2u, list.size());
 267   EXPECT_EQ(15, list[0]);
 268   EXPECT_EQ(10, list[1]);
 269   list.clear();
 270
 271   TestPlatformEventDispatcher overriding_dispatcher(20, &list);
 272   source()->RemovePlatformEventDispatcher(&overriding_dispatcher);
 273   scoped_ptr<ScopedEventDispatcher> handle =
 274       source()->OverrideDispatcher(&overriding_dispatcher);
 275   source()->Dispatch(*event);
 276   ASSERT_EQ(2u, list.size());
 277   EXPECT_EQ(15, list[0]);
 278   EXPECT_EQ(20, list[1]);
 279 }
 280
 281 // Tests that an overridden dispatcher can request that the default dispatchers
 282 // can dispatch the events.
 283 TEST_F(PlatformEventTest, OverriddenDispatcherInvokeDefaultDispatcher) {
 284   std::vector<int> list;
 285   TestPlatformEventDispatcher dispatcher(10, &list);
 286   TestPlatformEventObserver observer(15, &list);
 287   TestPlatformEventDispatcher overriding_dispatcher(20, &list);
 288   source()->RemovePlatformEventDispatcher(&overriding_dispatcher);
 289   scoped_ptr<ScopedEventDispatcher> handle =
 290       source()->OverrideDispatcher(&overriding_dispatcher);
 291   overriding_dispatcher.set_post_dispatch_action(POST_DISPATCH_PERFORM_DEFAULT);
 292
 293   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 294   source()->Dispatch(*event);
 295   // First the observer, then the overriding dispatcher, then the default
 296   // dispatcher.
 297   ASSERT_EQ(3u, list.size());
 298   EXPECT_EQ(15, list[0]);
 299   EXPECT_EQ(20, list[1]);
 300   EXPECT_EQ(10, list[2]);
 301   list.clear();
 302
 303   // Install a second overriding dispatcher.
 304   TestPlatformEventDispatcher second_overriding(50, &list);
 305   source()->RemovePlatformEventDispatcher(&second_overriding);
 306   scoped_ptr<ScopedEventDispatcher> second_override_handle =
 307       source()->OverrideDispatcher(&second_overriding);
 308   source()->Dispatch(*event);
 309   ASSERT_EQ(2u, list.size());
 310   EXPECT_EQ(15, list[0]);
 311   EXPECT_EQ(50, list[1]);
 312   list.clear();
 313
 314   second_overriding.set_post_dispatch_action(POST_DISPATCH_PERFORM_DEFAULT);
 315   source()->Dispatch(*event);
 316   // First the observer, then the second overriding dispatcher, then the default
 317   // dispatcher.
 318   ASSERT_EQ(3u, list.size());
 319   EXPECT_EQ(15, list[0]);
 320   EXPECT_EQ(50, list[1]);
 321   EXPECT_EQ(10, list[2]);
 322 }
 323
 324 // Runs a callback during an event dispatch.
 325 class RunCallbackDuringDispatch : public TestPlatformEventDispatcher {
 326  public:
 327   RunCallbackDuringDispatch(int id, std::vector<int>* list)
 328       : TestPlatformEventDispatcher(id, list) {}
 329   ~RunCallbackDuringDispatch() override {}
 330
 331   void set_callback(const base::Closure& callback) {
 332     callback_ = callback;
 333   }
 334
 335  protected:
 336   // PlatformEventDispatcher:
 337   uint32_t DispatchEvent(const PlatformEvent& event) override {
 338     if (!callback_.is_null())
 339       callback_.Run();
 340     return TestPlatformEventDispatcher::DispatchEvent(event);
 341   }
 342
 343  private:
 344   base::Closure callback_;
 345
 346   DISALLOW_COPY_AND_ASSIGN(RunCallbackDuringDispatch);
 347 };
 348
 349 // Test that if a dispatcher removes another dispatcher that is later in the
 350 // dispatcher list during dispatching an event, then event dispatching still
 351 // continues correctly.
 352 TEST_F(PlatformEventTest, DispatcherRemovesNextDispatcherDuringDispatch) {
 353   std::vector<int> list;
 354   TestPlatformEventDispatcher first(10, &list);
 355   RunCallbackDuringDispatch second(15, &list);
 356   TestPlatformEventDispatcher third(20, &list);
 357   TestPlatformEventDispatcher fourth(30, &list);
 358
 359   second.set_callback(base::Bind(&RemoveDispatcher, base::Unretained(&third)));
 360
 361   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 362   source()->Dispatch(*event);
 363   // |second| removes |third| from the dispatcher list during dispatch. So the
 364   // event should only reach |first|, |second|, and |fourth|.
 365   ASSERT_EQ(3u, list.size());
 366   EXPECT_EQ(10, list[0]);
 367   EXPECT_EQ(15, list[1]);
 368   EXPECT_EQ(30, list[2]);
 369 }
 370
 371 // Tests that if a dispatcher removes itself from the dispatcher list during
 372 // dispatching an event, then event dispatching continues correctly.
 373 TEST_F(PlatformEventTest, DispatcherRemovesSelfDuringDispatch) {
 374   std::vector<int> list;
 375   TestPlatformEventDispatcher first(10, &list);
 376   RunCallbackDuringDispatch second(15, &list);
 377   TestPlatformEventDispatcher third(20, &list);
 378
 379   second.set_callback(base::Bind(&RemoveDispatcher, base::Unretained(&second)));
 380
 381   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 382   source()->Dispatch(*event);
 383   // |second| removes itself from the dispatcher list during dispatch. So the
 384   // event should reach all three dispatchers in the list.
 385   ASSERT_EQ(3u, list.size());
 386   EXPECT_EQ(10, list[0]);
 387   EXPECT_EQ(15, list[1]);
 388   EXPECT_EQ(20, list[2]);
 389 }
 390
 391 // Tests that if a dispatcher removes itself from the dispatcher list during
 392 // dispatching an event, and this dispatcher is last in the dispatcher-list,
 393 // then event dispatching ends correctly.
 394 TEST_F(PlatformEventTest, DispatcherRemovesSelfDuringDispatchLast) {
 395   std::vector<int> list;
 396   TestPlatformEventDispatcher first(10, &list);
 397   RunCallbackDuringDispatch second(15, &list);
 398
 399   second.set_callback(base::Bind(&RemoveDispatcher, base::Unretained(&second)));
 400
 401   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 402   source()->Dispatch(*event);
 403   // |second| removes itself during dispatch. So both dispatchers will have
 404   // received the event.
 405   ASSERT_EQ(2u, list.size());
 406   EXPECT_EQ(10, list[0]);
 407   EXPECT_EQ(15, list[1]);
 408 }
 409
 410 // Tests that if a dispatcher removes a single dispatcher that comes before it
 411 // in the dispatcher list, then dispatch continues correctly.
 412 TEST_F(PlatformEventTest, DispatcherRemovesPrevDispatcherDuringDispatch) {
 413   std::vector<int> list;
 414   TestPlatformEventDispatcher first(10, &list);
 415   RunCallbackDuringDispatch second(15, &list);
 416   TestPlatformEventDispatcher third(20, &list);
 417
 418   second.set_callback(base::Bind(&RemoveDispatcher, base::Unretained(&first)));
 419
 420   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 421   source()->Dispatch(*event);
 422   // |second| removes |first| from the dispatcher list during dispatch. The
 423   // event should reach all three dispatchers.
 424   ASSERT_EQ(3u, list.size());
 425   EXPECT_EQ(10, list[0]);
 426   EXPECT_EQ(15, list[1]);
 427   EXPECT_EQ(20, list[2]);
 428 }
 429
 430 // Tests that if a dispatcher removes multiple dispatchers that comes before it
 431 // in the dispatcher list, then dispatch continues correctly.
 432 TEST_F(PlatformEventTest, DispatcherRemovesPrevDispatchersDuringDispatch) {
 433   std::vector<int> list;
 434   TestPlatformEventDispatcher first(10, &list);
 435   TestPlatformEventDispatcher second(12, &list);
 436   RunCallbackDuringDispatch third(15, &list);
 437   TestPlatformEventDispatcher fourth(20, &list);
 438
 439   third.set_callback(base::Bind(&RemoveDispatchers,
 440                                 base::Unretained(&first),
 441                                 base::Unretained(&second)));
 442
 443   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 444   source()->Dispatch(*event);
 445   // |third| removes |first| and |second| from the dispatcher list during
 446   // dispatch. The event should reach all three dispatchers.
 447   ASSERT_EQ(4u, list.size());
 448   EXPECT_EQ(10, list[0]);
 449   EXPECT_EQ(12, list[1]);
 450   EXPECT_EQ(15, list[2]);
 451   EXPECT_EQ(20, list[3]);
 452 }
 453
 454 // Tests that adding a dispatcher during dispatching an event receives that
 455 // event.
 456 TEST_F(PlatformEventTest, DispatcherAddedDuringDispatchReceivesEvent) {
 457   std::vector<int> list;
 458   TestPlatformEventDispatcher first(10, &list);
 459   RunCallbackDuringDispatch second(15, &list);
 460   TestPlatformEventDispatcher third(20, &list);
 461   TestPlatformEventDispatcher fourth(30, &list);
 462   RemoveDispatchers(&third, &fourth);
 463
 464   scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 465   source()->Dispatch(*event);
 466   ASSERT_EQ(2u, list.size());
 467   EXPECT_EQ(10, list[0]);
 468   EXPECT_EQ(15, list[1]);
 469
 470   second.set_callback(base::Bind(&AddDispatcher, base::Unretained(&third)));
 471   list.clear();
 472   source()->Dispatch(*event);
 473   ASSERT_EQ(3u, list.size());
 474   EXPECT_EQ(10, list[0]);
 475   EXPECT_EQ(15, list[1]);
 476   EXPECT_EQ(20, list[2]);
 477
 478   second.set_callback(base::Bind(&AddDispatcher, base::Unretained(&fourth)));
 479   list.clear();
 480   source()->Dispatch(*event);
 481   ASSERT_EQ(4u, list.size());
 482   EXPECT_EQ(10, list[0]);
 483   EXPECT_EQ(15, list[1]);
 484   EXPECT_EQ(20, list[2]);
 485   EXPECT_EQ(30, list[3]);
 486 }
 487
 488 // Provides mechanism for running tests from inside an active message-loop.
 489 class PlatformEventTestWithMessageLoop : public PlatformEventTest {
 490  public:
 491   PlatformEventTestWithMessageLoop() {}
 492   ~PlatformEventTestWithMessageLoop() override {}
 493
 494   void Run() {
 495     message_loop_.PostTask(
 496         FROM_HERE,
 497         base::Bind(&PlatformEventTestWithMessageLoop::RunTest,
 498                    base::Unretained(this)));
 499     message_loop_.Run();
 500   }
 501
 502  protected:
 503   void RunTest() {
 504     RunTestImpl();
 505     message_loop_.Quit();
 506   }
 507
 508   virtual void RunTestImpl() = 0;
 509
 510  private:
 511   base::MessageLoopForUI message_loop_;
 512
 513   DISALLOW_COPY_AND_ASSIGN(PlatformEventTestWithMessageLoop);
 514 };
 515
 516 #define RUN_TEST_IN_MESSAGE_LOOP(name) \
 517   TEST_F(name, Run) { Run(); }
 518
 519 // Tests that a ScopedEventDispatcher restores the previous dispatcher when
 520 // destroyed.
 521 class ScopedDispatcherRestoresAfterDestroy
 522     : public PlatformEventTestWithMessageLoop {
 523  public:
 524   // PlatformEventTestWithMessageLoop:
 525   void RunTestImpl() override {
 526     std::vector<int> list;
 527     TestPlatformEventDispatcher dispatcher(10, &list);
 528     TestPlatformEventObserver observer(15, &list);
 529
 530     TestPlatformEventDispatcher first_overriding(20, &list);
 531     source()->RemovePlatformEventDispatcher(&first_overriding);
 532     scoped_ptr<ScopedEventDispatcher> first_override_handle =
 533         source()->OverrideDispatcher(&first_overriding);
 534
 535     // Install a second overriding dispatcher.
 536     TestPlatformEventDispatcher second_overriding(50, &list);
 537     source()->RemovePlatformEventDispatcher(&second_overriding);
 538     scoped_ptr<ScopedEventDispatcher> second_override_handle =
 539         source()->OverrideDispatcher(&second_overriding);
 540
 541     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 542     source()->Dispatch(*event);
 543     ASSERT_EQ(2u, list.size());
 544     EXPECT_EQ(15, list[0]);
 545     EXPECT_EQ(50, list[1]);
 546     list.clear();
 547
 548     second_override_handle.reset();
 549     source()->Dispatch(*event);
 550     ASSERT_EQ(2u, list.size());
 551     EXPECT_EQ(15, list[0]);
 552     EXPECT_EQ(20, list[1]);
 553   }
 554 };
 555
 556 RUN_TEST_IN_MESSAGE_LOOP(ScopedDispatcherRestoresAfterDestroy)
 557
 558 // This dispatcher destroys the handle to the ScopedEventDispatcher when
 559 // dispatching an event.
 560 class DestroyScopedHandleDispatcher : public TestPlatformEventDispatcher {
 561  public:
 562   DestroyScopedHandleDispatcher(int id, std::vector<int>* list)
 563       : TestPlatformEventDispatcher(id, list) {}
 564   ~DestroyScopedHandleDispatcher() override {}
 565
 566   void SetScopedHandle(scoped_ptr<ScopedEventDispatcher> handler) {
 567     handler_ = handler.Pass();
 568   }
 569
 570   void set_callback(const base::Closure& callback) {
 571     callback_ = callback;
 572   }
 573
 574  private:
 575   // PlatformEventDispatcher:
 576   bool CanDispatchEvent(const PlatformEvent& event) override { return true; }
 577
 578   uint32_t DispatchEvent(const PlatformEvent& event) override {
 579     handler_.reset();
 580     uint32_t action = TestPlatformEventDispatcher::DispatchEvent(event);
 581     if (!callback_.is_null()) {
 582       callback_.Run();
 583       callback_ = base::Closure();
 584     }
 585     return action;
 586   }
 587
 588   scoped_ptr<ScopedEventDispatcher> handler_;
 589   base::Closure callback_;
 590
 591   DISALLOW_COPY_AND_ASSIGN(DestroyScopedHandleDispatcher);
 592 };
 593
 594 // Tests that resetting an overridden dispatcher causes the nested message-loop
 595 // iteration to stop and the rest of the events are dispatched in the next
 596 // iteration.
 597 class DestroyedNestedOverriddenDispatcherQuitsNestedLoopIteration
 598     : public PlatformEventTestWithMessageLoop {
 599  public:
 600   void NestedTask(std::vector<int>* list,
 601                   TestPlatformEventDispatcher* dispatcher) {
 602     ScopedVector<PlatformEvent> events;
 603     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 604     events.push_back(event.release());
 605     event = CreatePlatformEvent();
 606     events.push_back(event.release());
 607
 608     // Attempt to dispatch a couple of events. Dispatching the first event will
 609     // have terminated the ScopedEventDispatcher object, which will terminate
 610     // the current iteration of the message-loop.
 611     size_t count = source()->DispatchEventStream(events);
 612     EXPECT_EQ(1u, count);
 613     ASSERT_EQ(2u, list->size());
 614     EXPECT_EQ(15, (*list)[0]);
 615     EXPECT_EQ(20, (*list)[1]);
 616     list->clear();
 617
 618     ASSERT_LT(count, events.size());
 619     events.erase(events.begin(), events.begin() + count);
 620
 621     count = source()->DispatchEventStream(events);
 622     EXPECT_EQ(1u, count);
 623     ASSERT_EQ(2u, list->size());
 624     EXPECT_EQ(15, (*list)[0]);
 625     EXPECT_EQ(10, (*list)[1]);
 626     list->clear();
 627
 628     // Terminate the message-loop.
 629     base::MessageLoopForUI::current()->QuitNow();
 630   }
 631
 632   // PlatformEventTestWithMessageLoop:
 633   void RunTestImpl() override {
 634     std::vector<int> list;
 635     TestPlatformEventDispatcher dispatcher(10, &list);
 636     TestPlatformEventObserver observer(15, &list);
 637
 638     DestroyScopedHandleDispatcher overriding(20, &list);
 639     source()->RemovePlatformEventDispatcher(&overriding);
 640     scoped_ptr<ScopedEventDispatcher> override_handle =
 641         source()->OverrideDispatcher(&overriding);
 642
 643     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 644     source()->Dispatch(*event);
 645     ASSERT_EQ(2u, list.size());
 646     EXPECT_EQ(15, list[0]);
 647     EXPECT_EQ(20, list[1]);
 648     list.clear();
 649
 650     overriding.SetScopedHandle(override_handle.Pass());
 651     base::RunLoop run_loop;
 652     base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
 653     base::MessageLoopForUI::ScopedNestableTaskAllower allow_nested(loop);
 654     loop->PostTask(
 655         FROM_HERE,
 656         base::Bind(
 657             &DestroyedNestedOverriddenDispatcherQuitsNestedLoopIteration::
 658                 NestedTask,
 659             base::Unretained(this),
 660             base::Unretained(&list),
 661             base::Unretained(&overriding)));
 662     run_loop.Run();
 663
 664     // Dispatching the event should now reach the default dispatcher.
 665     source()->Dispatch(*event);
 666     ASSERT_EQ(2u, list.size());
 667     EXPECT_EQ(15, list[0]);
 668     EXPECT_EQ(10, list[1]);
 669   }
 670 };
 671
 672 RUN_TEST_IN_MESSAGE_LOOP(
 673     DestroyedNestedOverriddenDispatcherQuitsNestedLoopIteration)
 674
 675 // Tests that resetting an overridden dispatcher, and installing another
 676 // overridden dispatcher before the nested message-loop completely unwinds
 677 // function correctly.
 678 class ConsecutiveOverriddenDispatcherInTheSameMessageLoopIteration
 679     : public PlatformEventTestWithMessageLoop {
 680  public:
 681   void NestedTask(scoped_ptr<ScopedEventDispatcher> dispatch_handle,
 682                   std::vector<int>* list) {
 683     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 684     source()->Dispatch(*event);
 685     ASSERT_EQ(2u, list->size());
 686     EXPECT_EQ(15, (*list)[0]);
 687     EXPECT_EQ(20, (*list)[1]);
 688     list->clear();
 689
 690     // Reset the override dispatcher. This should restore the default
 691     // dispatcher.
 692     dispatch_handle.reset();
 693     source()->Dispatch(*event);
 694     ASSERT_EQ(2u, list->size());
 695     EXPECT_EQ(15, (*list)[0]);
 696     EXPECT_EQ(10, (*list)[1]);
 697     list->clear();
 698
 699     // Install another override-dispatcher.
 700     DestroyScopedHandleDispatcher second_overriding(70, list);
 701     source()->RemovePlatformEventDispatcher(&second_overriding);
 702     scoped_ptr<ScopedEventDispatcher> second_override_handle =
 703         source()->OverrideDispatcher(&second_overriding);
 704
 705     source()->Dispatch(*event);
 706     ASSERT_EQ(2u, list->size());
 707     EXPECT_EQ(15, (*list)[0]);
 708     EXPECT_EQ(70, (*list)[1]);
 709     list->clear();
 710
 711     second_overriding.SetScopedHandle(second_override_handle.Pass());
 712     second_overriding.set_post_dispatch_action(POST_DISPATCH_NONE);
 713     base::RunLoop run_loop;
 714     second_overriding.set_callback(run_loop.QuitClosure());
 715     base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
 716     base::MessageLoopForUI::ScopedNestableTaskAllower allow_nested(loop);
 717     loop->PostTask(
 718         FROM_HERE,
 719         base::Bind(base::IgnoreResult(&TestPlatformEventSource::Dispatch),
 720                    base::Unretained(source()),
 721                    *event));
 722     run_loop.Run();
 723     ASSERT_EQ(2u, list->size());
 724     EXPECT_EQ(15, (*list)[0]);
 725     EXPECT_EQ(70, (*list)[1]);
 726     list->clear();
 727
 728     // Terminate the message-loop.
 729     base::MessageLoopForUI::current()->QuitNow();
 730   }
 731
 732   // PlatformEventTestWithMessageLoop:
 733   void RunTestImpl() override {
 734     std::vector<int> list;
 735     TestPlatformEventDispatcher dispatcher(10, &list);
 736     TestPlatformEventObserver observer(15, &list);
 737
 738     TestPlatformEventDispatcher overriding(20, &list);
 739     source()->RemovePlatformEventDispatcher(&overriding);
 740     scoped_ptr<ScopedEventDispatcher> override_handle =
 741         source()->OverrideDispatcher(&overriding);
 742
 743     scoped_ptr<PlatformEvent> event(CreatePlatformEvent());
 744     source()->Dispatch(*event);
 745     ASSERT_EQ(2u, list.size());
 746     EXPECT_EQ(15, list[0]);
 747     EXPECT_EQ(20, list[1]);
 748     list.clear();
 749
 750     // Start a nested message-loop, and destroy |override_handle| in the nested
 751     // loop. That should terminate the nested loop, restore the previous
 752     // dispatchers, and return control to this function.
 753     base::RunLoop run_loop;
 754     base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
 755     base::MessageLoopForUI::ScopedNestableTaskAllower allow_nested(loop);
 756     loop->PostTask(
 757         FROM_HERE,
 758         base::Bind(
 759             &ConsecutiveOverriddenDispatcherInTheSameMessageLoopIteration::
 760                 NestedTask,
 761             base::Unretained(this),
 762             base::Passed(&override_handle),
 763             base::Unretained(&list)));
 764     run_loop.Run();
 765
 766     // Dispatching the event should now reach the default dispatcher.
 767     source()->Dispatch(*event);
 768     ASSERT_EQ(2u, list.size());
 769     EXPECT_EQ(15, list[0]);
 770     EXPECT_EQ(10, list[1]);
 771   }
 772 };
 773
 774 RUN_TEST_IN_MESSAGE_LOOP(
 775     ConsecutiveOverriddenDispatcherInTheSameMessageLoopIteration)
 776
 777 }  // namespace ui