Revert of Use FileDescriptorWatcher in AlarmTimer.

components/timers/alarm_timer_unittest.cc

Index: components/timers/alarm_timer_unittest.cc
diff --git a/components/timers/alarm_timer_unittest.cc b/components/timers/alarm_timer_unittest.cc
index 2dbd51bfd81cc1700822e03d5f9d8d9fd4fc6885..2b9663dc65ad37612296cb0d7b6fc8b4244cd8c9 100644
--- a/components/timers/alarm_timer_unittest.cc
+++ b/components/timers/alarm_timer_unittest.cc
@@ -8,10 +8,8 @@
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
-#include "base/files/file_descriptor_watcher_posix.h"
 #include "base/location.h"
 #include "base/macros.h"
-#include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
@@ -25,8 +23,22 @@
 // cosmetic changes (like replacing calls to MessageLoop::current()->Run() with
 // a RunLoop).  We want the AlarmTimer to be a drop-in replacement for the
 // regular Timer so it should pass the same tests as the Timer class.
+//
+// The only new tests are the .*ConcurrentResetAndTimerFired tests, which test
+// that race conditions that can come up in the AlarmTimer::Delegate are
+// properly handled.
 namespace timers {
 namespace {
+// The message loops on which each timer should be tested.
+const base::MessageLoop::Type testing_message_loops[] = {
+    base::MessageLoop::TYPE_DEFAULT,
+    base::MessageLoop::TYPE_IO,
+#if !defined(OS_IOS)  // iOS does not allow direct running of the UI loop.
+    base::MessageLoop::TYPE_UI,
+#endif
+};
+
+const int kNumTestingMessageLoops = arraysize(testing_message_loops);
 const base::TimeDelta kTenMilliseconds = base::TimeDelta::FromMilliseconds(10);
 
 class OneShotAlarmTimerTester {
@@ -121,129 +133,136 @@
 // that timers work properly in all configurations.
 
 TEST(AlarmTimerTest, OneShotAlarmTimer) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run = false;
-  OneShotAlarmTimerTester f(&did_run, kTenMilliseconds);
-  f.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_TRUE(did_run);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run = false;
+    OneShotAlarmTimerTester f(&did_run, kTenMilliseconds);
+    f.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_TRUE(did_run);
+  }
 }
 
 TEST(AlarmTimerTest, OneShotAlarmTimer_Cancel) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run_a = false;
-  OneShotAlarmTimerTester* a =
-      new OneShotAlarmTimerTester(&did_run_a, kTenMilliseconds);
-
-  // This should run before the timer expires.
-  base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
-
-  // Now start the timer.
-  a->Start();
-
-  bool did_run_b = false;
-  OneShotAlarmTimerTester b(&did_run_b, kTenMilliseconds);
-  b.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_FALSE(did_run_a);
-  EXPECT_TRUE(did_run_b);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run_a = false;
+    OneShotAlarmTimerTester* a =
+        new OneShotAlarmTimerTester(&did_run_a, kTenMilliseconds);
+
+    // This should run before the timer expires.
+    base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
+
+    // Now start the timer.
+    a->Start();
+
+    bool did_run_b = false;
+    OneShotAlarmTimerTester b(&did_run_b, kTenMilliseconds);
+    b.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_FALSE(did_run_a);
+    EXPECT_TRUE(did_run_b);
+  }
 }
 
 // If underlying timer does not handle this properly, we will crash or fail
 // in full page heap environment.
 TEST(AlarmTimerTest, OneShotSelfDeletingAlarmTimer) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run = false;
-  OneShotSelfDeletingAlarmTimerTester f(&did_run, kTenMilliseconds);
-  f.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_TRUE(did_run);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run = false;
+    OneShotSelfDeletingAlarmTimerTester f(&did_run, kTenMilliseconds);
+    f.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_TRUE(did_run);
+  }
 }
 
 TEST(AlarmTimerTest, RepeatingAlarmTimer) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run = false;
-  RepeatingAlarmTimerTester f(&did_run, kTenMilliseconds);
-  f.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_TRUE(did_run);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run = false;
+    RepeatingAlarmTimerTester f(&did_run, kTenMilliseconds);
+    f.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_TRUE(did_run);
+  }
 }
 
 TEST(AlarmTimerTest, RepeatingAlarmTimer_Cancel) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run_a = false;
-  RepeatingAlarmTimerTester* a =
-      new RepeatingAlarmTimerTester(&did_run_a, kTenMilliseconds);
-
-  // This should run before the timer expires.
-  base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
-
-  // Now start the timer.
-  a->Start();
-
-  bool did_run_b = false;
-  RepeatingAlarmTimerTester b(&did_run_b, kTenMilliseconds);
-  b.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_FALSE(did_run_a);
-  EXPECT_TRUE(did_run_b);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run_a = false;
+    RepeatingAlarmTimerTester* a =
+        new RepeatingAlarmTimerTester(&did_run_a, kTenMilliseconds);
+
+    // This should run before the timer expires.
+    base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
+
+    // Now start the timer.
+    a->Start();
+
+    bool did_run_b = false;
+    RepeatingAlarmTimerTester b(&did_run_b, kTenMilliseconds);
+    b.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_FALSE(did_run_a);
+    EXPECT_TRUE(did_run_b);
+  }
 }
 
 TEST(AlarmTimerTest, RepeatingAlarmTimerZeroDelay) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run = false;
-  RepeatingAlarmTimerTester f(&did_run, base::TimeDelta());
-  f.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_TRUE(did_run);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run = false;
+    RepeatingAlarmTimerTester f(&did_run, base::TimeDelta());
+    f.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_TRUE(did_run);
+  }
 }
 
 TEST(AlarmTimerTest, RepeatingAlarmTimerZeroDelay_Cancel) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-
-  bool did_run_a = false;
-  RepeatingAlarmTimerTester* a =
-      new RepeatingAlarmTimerTester(&did_run_a, base::TimeDelta());
-
-  // This should run before the timer expires.
-  base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
-
-  // Now start the timer.
-  a->Start();
-
-  bool did_run_b = false;
-  RepeatingAlarmTimerTester b(&did_run_b, base::TimeDelta());
-  b.Start();
-
-  base::RunLoop().Run();
-
-  EXPECT_FALSE(did_run_a);
-  EXPECT_TRUE(did_run_b);
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    bool did_run_a = false;
+    RepeatingAlarmTimerTester* a =
+        new RepeatingAlarmTimerTester(&did_run_a, base::TimeDelta());
+
+    // This should run before the timer expires.
+    base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, a);
+
+    // Now start the timer.
+    a->Start();
+
+    bool did_run_b = false;
+    RepeatingAlarmTimerTester b(&did_run_b, base::TimeDelta());
+    b.Start();
+
+    base::RunLoop().Run();
+
+    EXPECT_FALSE(did_run_a);
+    EXPECT_TRUE(did_run_b);
+  }
 }
 
 TEST(AlarmTimerTest, MessageLoopShutdown) {
@@ -253,29 +272,23 @@
   // if debug heap checking is enabled.
   bool did_run = false;
   {
-    auto loop = base::MakeUnique<base::MessageLoopForIO>();
-    auto file_descriptor_watcher =
-        base::MakeUnique<base::FileDescriptorWatcher>(loop.get());
     OneShotAlarmTimerTester a(&did_run, kTenMilliseconds);
     OneShotAlarmTimerTester b(&did_run, kTenMilliseconds);
     OneShotAlarmTimerTester c(&did_run, kTenMilliseconds);
     OneShotAlarmTimerTester d(&did_run, kTenMilliseconds);
-
-    a.Start();
-    b.Start();
-
-    // MessageLoop and FileDescriptorWatcher destruct.
-    file_descriptor_watcher.reset();
-    loop.reset();
-  }  // OneShotTimers destruct. SHOULD NOT CRASH, of course.
+    {
+      base::MessageLoop loop;
+      a.Start();
+      b.Start();
+    }  // MessageLoop destructs by falling out of scope.
+  }    // OneShotTimers destruct.  SHOULD NOT CRASH, of course.
 
   EXPECT_FALSE(did_run);
 }
 
 TEST(AlarmTimerTest, NonRepeatIsRunning) {
   {
-    base::MessageLoopForIO loop;
-    base::FileDescriptorWatcher file_descriptor_watcher(&loop);
+    base::MessageLoop loop;
     timers::OneShotAlarmTimer timer;
     EXPECT_FALSE(timer.IsRunning());
     timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
@@ -287,9 +300,8 @@
   }
 
   {
-    base::MessageLoopForIO loop;
-    base::FileDescriptorWatcher file_descriptor_watcher(&loop);
     timers::SimpleAlarmTimer timer;
+    base::MessageLoop loop;
     EXPECT_FALSE(timer.IsRunning());
     timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
                 base::Bind(&base::DoNothing));
@@ -302,14 +314,24 @@
   }
 }
 
+TEST(AlarmTimerTest, NonRepeatMessageLoopDeath) {
+  timers::OneShotAlarmTimer timer;
+  {
+    base::MessageLoop loop;
+    EXPECT_FALSE(timer.IsRunning());
+    timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
+                base::Bind(&base::DoNothing));
+    EXPECT_TRUE(timer.IsRunning());
+  }
+  EXPECT_FALSE(timer.IsRunning());
+  EXPECT_TRUE(timer.user_task().is_null());
+}
+
 TEST(AlarmTimerTest, RetainRepeatIsRunning) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  timers::RepeatingAlarmTimer timer;
+  base::MessageLoop loop;
+  timers::RepeatingAlarmTimer timer(FROM_HERE, base::TimeDelta::FromDays(1),
+                                    base::Bind(&base::DoNothing));
   EXPECT_FALSE(timer.IsRunning());
-  timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
-              base::Bind(&base::DoNothing));
-  EXPECT_TRUE(timer.IsRunning());
   timer.Reset();
   EXPECT_TRUE(timer.IsRunning());
   timer.Stop();
@@ -319,13 +341,10 @@
 }
 
 TEST(AlarmTimerTest, RetainNonRepeatIsRunning) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  timers::SimpleAlarmTimer timer;
+  base::MessageLoop loop;
+  timers::SimpleAlarmTimer timer(FROM_HERE, base::TimeDelta::FromDays(1),
+                                 base::Bind(&base::DoNothing));
   EXPECT_FALSE(timer.IsRunning());
-  timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
-              base::Bind(&base::DoNothing));
-  EXPECT_TRUE(timer.IsRunning());
   timer.Reset();
   EXPECT_TRUE(timer.IsRunning());
   timer.Stop();
@@ -357,75 +376,142 @@
 }
 
 TEST(AlarmTimerTest, ContinuationStopStart) {
-  ClearAllCallbackHappened();
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  timers::OneShotAlarmTimer timer;
-  timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
-              base::Bind(&SetCallbackHappened1));
-  timer.Stop();
-  timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(40),
-              base::Bind(&SetCallbackHappened2));
-  base::RunLoop().Run();
-  EXPECT_FALSE(g_callback_happened1);
-  EXPECT_TRUE(g_callback_happened2);
+  {
+    ClearAllCallbackHappened();
+    base::MessageLoop loop;
+    timers::OneShotAlarmTimer timer;
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
+                base::Bind(&SetCallbackHappened1));
+    timer.Stop();
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(40),
+                base::Bind(&SetCallbackHappened2));
+    base::RunLoop().Run();
+    EXPECT_FALSE(g_callback_happened1);
+    EXPECT_TRUE(g_callback_happened2);
+  }
 }
 
 TEST(AlarmTimerTest, ContinuationReset) {
-  ClearAllCallbackHappened();
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  timers::OneShotAlarmTimer timer;
-  timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
-              base::Bind(&SetCallbackHappened1));
-  timer.Reset();
-  // Since Reset happened before task ran, the user_task must not be cleared:
-  ASSERT_FALSE(timer.user_task().is_null());
-  base::RunLoop().Run();
-  EXPECT_TRUE(g_callback_happened1);
-}
-
-// Verify that no crash occurs if a timer is deleted while its callback is
-// running.
-TEST(AlarmTimerTest, DeleteTimerWhileCallbackIsRunning) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  base::RunLoop run_loop;
-
-  // Will be deleted by the callback.
-  timers::OneShotAlarmTimer* timer = new timers::OneShotAlarmTimer;
-
-  timer->Start(
-      FROM_HERE, base::TimeDelta::FromMilliseconds(10),
-      base::Bind(
-          [](timers::OneShotAlarmTimer* timer, base::RunLoop* run_loop) {
-            delete timer;
-            run_loop->Quit();
-          },
-          timer, &run_loop));
-  run_loop.Run();
-}
-
-// Verify that no crash occurs if a zero-delay timer is deleted while its
-// callback is running.
-TEST(AlarmTimerTest, DeleteTimerWhileCallbackIsRunningZeroDelay) {
-  base::MessageLoopForIO loop;
-  base::FileDescriptorWatcher file_descriptor_watcher(&loop);
-  base::RunLoop run_loop;
-
-  // Will be deleted by the callback.
-  timers::OneShotAlarmTimer* timer = new timers::OneShotAlarmTimer;
-
-  timer->Start(
-      FROM_HERE, base::TimeDelta(),
-      base::Bind(
-          [](timers::OneShotAlarmTimer* timer, base::RunLoop* run_loop) {
-            delete timer;
-            run_loop->Quit();
-          },
-          timer, &run_loop));
-  run_loop.Run();
+  {
+    ClearAllCallbackHappened();
+    base::MessageLoop loop;
+    timers::OneShotAlarmTimer timer;
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
+                base::Bind(&SetCallbackHappened1));
+    timer.Reset();
+    // Since Reset happened before task ran, the user_task must not be cleared:
+    ASSERT_FALSE(timer.user_task().is_null());
+    base::RunLoop().Run();
+    EXPECT_TRUE(g_callback_happened1);
+  }
 }
 
 }  // namespace
+
+namespace {
+void TimerRanCallback(bool* did_run) {
+  *did_run = true;
+
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+}
+
+bool IsAlarmTimerSupported() {
+  int fd = timerfd_create(CLOCK_REALTIME_ALARM, 0);
+
+  if (fd == -1) {
+    LOG(WARNING) << "CLOCK_REALTIME_ALARM is not supported on this system.  "
+                 << "Skipping test.  Upgrade to at least linux version 3.11 to "
+                 << "support this timer.";
+    return false;
+  }
+
+  close(fd);
+  return true;
+}
+
+TEST(AlarmTimerTest, OneShotTimerConcurrentResetAndTimerFired) {
+  // The "Linux ChromiumOS .*" bots are still running Ubuntu 12.04, which
+  // doesn't have a linux version high enough to support the AlarmTimer.  Since
+  // this test depends on SetTimerFiredCallbackForTest(), which is specific to
+  // the AlarmTimer, we have to just skip the test to stop it from failing.
+  if (!IsAlarmTimerSupported())
+    return;
+
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    timers::OneShotAlarmTimer timer;
+    bool did_run = false;
+
+    base::RunLoop run_loop;
+
+    timer.SetTimerFiredCallbackForTest(run_loop.QuitClosure());
+    timer.Start(FROM_HERE, kTenMilliseconds,
+                base::Bind(&TimerRanCallback, &did_run));
+
+    // Wait until the timer has fired and a task has been queue in the
+    // MessageLoop.
+    run_loop.Run();
+
+    // Now reset the timer.  This is attempting to simulate the timer firing and
+    // being reset at the same time.  The previously queued task should be
+    // removed.
+    timer.Reset();
+
+    base::RunLoop().RunUntilIdle();
+    EXPECT_FALSE(did_run);
+
+    // If the previous check failed, running the message loop again will hang
+    // the test so we only do it if the callback has not run yet.
+    if (!did_run) {
+      base::RunLoop().Run();
+      EXPECT_TRUE(did_run);
+    }
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingTimerConcurrentResetAndTimerFired) {
+  // The "Linux ChromiumOS .*" bots are still running Ubuntu 12.04, which
+  // doesn't have a linux version high enough to support the AlarmTimer.  Since
+  // this test depends on SetTimerFiredCallbackForTest(), which is specific to
+  // the AlarmTimer, we have to just skip the test to stop it from failing.
+  if (!IsAlarmTimerSupported())
+    return;
+
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    base::MessageLoop loop(testing_message_loops[i]);
+
+    timers::RepeatingAlarmTimer timer;
+    bool did_run = false;
+
+    base::RunLoop run_loop;
+
+    timer.SetTimerFiredCallbackForTest(run_loop.QuitClosure());
+    timer.Start(FROM_HERE, kTenMilliseconds,
+                base::Bind(&TimerRanCallback, &did_run));
+
+    // Wait until the timer has fired and a task has been queue in the
+    // MessageLoop.
+    run_loop.Run();
+
+    // Now reset the timer.  This is attempting to simulate the timer firing and
+    // being reset at the same time.  The previously queued task should be
+    // removed.
+    timer.Reset();
+
+    base::RunLoop().RunUntilIdle();
+    EXPECT_FALSE(did_run);
+
+    // If the previous check failed, running the message loop again will hang
+    // the test so we only do it if the callback has not run yet.
+    if (!did_run) {
+      base::RunLoop().Run();
+      EXPECT_TRUE(did_run);
+    }
+  }
+}
+
+}  // namespace
+
 }  // namespace timers