Refactor TimeBase to post tasks. Workers to use real Idle tasks.

Source/platform/TimerTest.cpp

Index: Source/platform/TimerTest.cpp
diff --git a/Source/platform/TimerTest.cpp b/Source/platform/TimerTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..ee2542e4533ea3dfb955f18041274391ec386ff1
--- /dev/null
+++ b/Source/platform/TimerTest.cpp
@@ -0,0 +1,680 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "platform/Timer.h"
+
+#include "public/platform/Platform.h"
+#include "public/platform/WebScheduler.h"
+#include "public/platform/WebThread.h"
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <queue>
+
+using testing::ElementsAre;
+
+namespace blink {
+namespace {
+double gCurrentTimeSecs = 0.0;
+
+double CurrentTime()
+{
+    return gCurrentTimeSecs;
+}
+
+// This class exists because gcc doesn't know how to move an OwnPtr.
+class RefCountedTaskContainer : public RefCounted<RefCountedTaskContainer> {
+public:
+    explicit RefCountedTaskContainer(WebThread::Task* task) : m_task(adoptPtr(task)) { }
+
+    ~RefCountedTaskContainer() { }
+
+    void run()
+    {
+        m_task->run();
+    }
+
+private:
+    OwnPtr<WebThread::Task> m_task;
+};
+
+class DelayedTask {
+public:
+    DelayedTask(WebThread::Task* task, long long delayMs)
+        : m_task(adoptRef(new RefCountedTaskContainer(task)))
+        , m_runTimeSecs(monotonicallyIncreasingTime() + 0.001 * static_cast<double>(delayMs))
+        , m_delayMs(delayMs) { }
+
+    bool operator<(const DelayedTask& other) const
+    {
+        return m_runTimeSecs > other.m_runTimeSecs;
+    }
+
+    void run() const
+    {
+        m_task->run();
+    }
+
+    double runTimeSecs() const
+    {
+        return m_runTimeSecs;
+    }
+
+    long long delayMs() const
+    {
+        return m_delayMs;
+    }
+
+private:
+    RefPtr<RefCountedTaskContainer> m_task;
+    double m_runTimeSecs;
+    long long m_delayMs;
+};
+
+class MockWebScheduler : public WebScheduler {
+public:
+    explicit MockWebScheduler(std::priority_queue<DelayedTask>* timerTasks) : m_timerTasks(timerTasks) { }
+    ~MockWebScheduler() override { }
+
+    bool shouldYieldForHighPriorityWork() override
+    {
+        return false;
+    }
+
+    bool canExceedIdleDeadlineIfRequired() override
+    {
+        return false;
+    }
+
+    void postIdleTask(const WebTraceLocation&, WebThread::IdleTask*) override
+    {
+    }
+
+    void postNonNestableIdleTask(const WebTraceLocation&, WebThread::IdleTask*) override
+    {
+    }
+
+    void postIdleTaskAfterWakeup(const WebTraceLocation&, WebThread::IdleTask*) override
+    {
+    }
+
+    void postLoadingTask(const WebTraceLocation&, WebThread::Task*) override
+    {
+    }
+
+    void postTimerTask(const WebTraceLocation&, WebThread::Task* task, long long delayMs) override
+    {
+        m_timerTasks->push(DelayedTask(task, delayMs));
+    }
+
+private:
+    std::priority_queue<DelayedTask>* m_timerTasks;
+};
+
+class FakeWebThread : public WebThread {
+public:
+    explicit FakeWebThread(WebScheduler* webScheduler) : m_webScheduler(webScheduler) { }
+    ~FakeWebThread() override { }
+
+    // WebThread implementation:
+    void postTask(const WebTraceLocation&, Task*)
+    {
+        ASSERT_NOT_REACHED();
+    }
+
+    virtual void postDelayedTask(const WebTraceLocation&, Task*, long long)
+    {
+        ASSERT_NOT_REACHED();
+    }
+
+    virtual bool isCurrentThread() const
+    {
+        ASSERT_NOT_REACHED();
+        return true;
+    }
+
+    virtual PlatformThreadId threadId() const
+    {
+        ASSERT_NOT_REACHED();
+        return 0;
+    }
+
+    WebScheduler* scheduler() const override
+    {
+        return m_webScheduler;
+    }
+
+    virtual void enterRunLoop()
+    {
+        ASSERT_NOT_REACHED();
+    }
+
+    virtual void exitRunLoop()
+    {
+        ASSERT_NOT_REACHED();
+    }
+
+private:
+    WebScheduler* m_webScheduler;
+};
+
+class TimerTestPlatform : public Platform {
+public:
+    explicit TimerTestPlatform(WebThread* webThread) : m_webThread(webThread) { }
+    ~TimerTestPlatform() override { }
+
+    WebThread* currentThread() override
+    {
+        return m_webThread;
+    }
+
+    void cryptographicallyRandomValues(unsigned char*, size_t) override
+    {
+        ASSERT_NOT_REACHED();
+    }
+
+private:
+    WebThread* m_webThread;
+};
+
+class TimerTest : public testing::Test {
+public:
+    void SetUp() override
+    {
+        m_timerTasks = adoptPtr(new std::priority_queue<DelayedTask>);
+        m_mockWebScheduler = adoptPtr(new MockWebScheduler(m_timerTasks.get()));
+        m_fakeWebThread = adoptPtr(new FakeWebThread(m_mockWebScheduler.get()));
+        m_platform = adoptPtr(new TimerTestPlatform(m_fakeWebThread.get()));
+        m_oldPlatform = Platform::current();
+        Platform::initialize(m_platform.get());
+        WTF::setMonotonicallyIncreasingTimeFunction(CurrentTime);
+
+        m_runTimes.clear();
+        gCurrentTimeSecs = 10.0;
+        m_startTime = gCurrentTimeSecs;
+    }
+
+    void TearDown() override
+    {
+        Platform::initialize(m_oldPlatform);
+    }
+
+    void CountingTask(Timer<TimerTest>*)
+    {
+        m_runTimes.push_back(monotonicallyIncreasingTime());
+    }
+
+    void AdvanceTimeTo(double timeSecs)
+    {
+        gCurrentTimeSecs = timeSecs;
+    }
+
+    void AdvanceTimeBy(double timeSecs)
+    {
+        gCurrentTimeSecs += timeSecs;
+    }
+
+    void RunUntilIdle()
+    {
+        while (!m_timerTasks->empty()) {
+            AdvanceTimeTo(m_timerTasks->top().runTimeSecs());
+            m_timerTasks->top().run();
+            m_timerTasks->pop();
+        }
+    }
+
+    void RunUntilIdleOrDeadlinePassed(double deadline)
+    {
+        while (!m_timerTasks->empty() && m_timerTasks->top().runTimeSecs() < deadline) {
+            AdvanceTimeTo(m_timerTasks->top().runTimeSecs());
+            m_timerTasks->top().run();
+            m_timerTasks->pop();
+        }
+    }
+
+protected:
+    double m_startTime;
+    std::vector<double> m_runTimes;
+    OwnPtr<std::priority_queue<DelayedTask>> m_timerTasks;
+
+private:
+    OwnPtr<MockWebScheduler> m_mockWebScheduler;
+    OwnPtr<FakeWebThread> m_fakeWebThread;
+    OwnPtr<TimerTestPlatform> m_platform;
+    Platform* m_oldPlatform;
+};
+
+TEST_F(TimerTest, StartOneShot_Zero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime));
+}
+
+TEST_F(TimerTest, StartOneShot_ZeroAndCancel)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    timer.stop();
+
+    RunUntilIdle();
+    EXPECT_TRUE(m_runTimes.empty());
+}
+
+TEST_F(TimerTest, StartOneShot_ZeroAndCancelThenRepost)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    timer.stop();
+
+    RunUntilIdle();
+    EXPECT_TRUE(m_runTimes.empty());
+
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime));
+}
+
+TEST_F(TimerTest, StartOneShot_Zero_RepostingAfterRunning)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime));
+
+    timer.startOneShot(0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(0ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime, m_startTime));
+}
+
+TEST_F(TimerTest, StartOneShot_NonZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10.0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 10.0));
+}
+
+TEST_F(TimerTest, StartOneShot_NonZeroAndCancel)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    timer.stop();
+
+    RunUntilIdle();
+    EXPECT_TRUE(m_runTimes.empty());
+}
+
+TEST_F(TimerTest, StartOneShot_NonZeroAndCancelThenRepost)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    timer.stop();
+
+    RunUntilIdle();
+    EXPECT_TRUE(m_runTimes.empty());
+
+    double secondPostTime = monotonicallyIncreasingTime();
+    timer.startOneShot(10, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(secondPostTime + 10.0));
+}
+
+TEST_F(TimerTest, StartOneShot_NonZero_RepostingAfterRunning)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 10.0));
+
+    timer.startOneShot(20, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(20000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 10.0, m_startTime + 30.0));
+}
+
+TEST_F(TimerTest, PostingTimerTwiceWithSameRunTimeDoesNothing)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+    timer.startOneShot(10, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(10000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 10.0));
+}
+
+TEST_F(TimerTest, PostingTimerTwiceWithNewerRunTimeCancelsOrigionalTask)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+    timer.startOneShot(0, FROM_HERE);
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 0.0));
+}
+
+TEST_F(TimerTest, PostingTimerTwiceWithLaterRunTimeCancelsOrigionalTask)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+    timer.startOneShot(10, FROM_HERE);
+
+    RunUntilIdle();
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 10.0));
+}
+
+TEST_F(TimerTest, StartRepeatingTask)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(1.0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(1000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdleOrDeadlinePassed(m_startTime + 5.5);
+    EXPECT_THAT(m_runTimes, ElementsAre(
+        m_startTime + 1.0, m_startTime + 2.0, m_startTime + 3.0, m_startTime + 4.0, m_startTime + 5.0));
+}
+
+TEST_F(TimerTest, StartRepeatingTask_ThenCancel)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(1.0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(1000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdleOrDeadlinePassed(m_startTime + 2.5);
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 1.0, m_startTime + 2.0));
+
+    timer.stop();
+    RunUntilIdle();
+
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 1.0, m_startTime + 2.0));
+}
+
+TEST_F(TimerTest, StartRepeatingTask_ThenPostOneShot)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(1.0, FROM_HERE);
+
+    ASSERT_EQ(1ul, m_timerTasks->size());
+    EXPECT_EQ(1000ll, m_timerTasks->top().delayMs());
+
+    RunUntilIdleOrDeadlinePassed(m_startTime + 2.5);
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 1.0, m_startTime + 2.0));
+
+    timer.startOneShot(0, FROM_HERE);
+    RunUntilIdle();
+
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 1.0, m_startTime + 2.0, m_startTime + 2.0));
+}
+
+TEST_F(TimerTest, IsActive_NeverPosted)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+
+    EXPECT_FALSE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterPosting_OneShotZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    EXPECT_TRUE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterPosting_OneShotNonZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    EXPECT_TRUE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterPosting_Repeating)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(1.0, FROM_HERE);
+
+    EXPECT_TRUE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterRunning_OneShotZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    RunUntilIdle();
+    EXPECT_FALSE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterRunning_OneShotNonZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    RunUntilIdle();
+    EXPECT_FALSE(timer.isActive());
+}
+
+TEST_F(TimerTest, IsActive_AfterRunning_Repeating)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(1.0, FROM_HERE);
+
+    RunUntilIdleOrDeadlinePassed(m_startTime + 10);
+    EXPECT_TRUE(timer.isActive()); // It should run until cancelled.
+}
+
+TEST_F(TimerTest, NextFireInterval_OneShotZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(0.0, timer.nextFireInterval());
+}
+
+TEST_F(TimerTest, NextFireInterval_OneShotNonZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(10.0, timer.nextFireInterval());
+}
+
+TEST_F(TimerTest, NextFireInterval_OneShotNonZero_AfterAFewSeconds)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    AdvanceTimeBy(2.0);
+    EXPECT_FLOAT_EQ(8.0, timer.nextFireInterval());
+}
+
+TEST_F(TimerTest, NextFireInterval_Repeating)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(20, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(20.0, timer.nextFireInterval());
+}
+
+TEST_F(TimerTest, RepeatInterval_NeverStarted)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+
+    EXPECT_FLOAT_EQ(0.0, timer.repeatInterval());
+}
+
+TEST_F(TimerTest, RepeatInterval_OneShotZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(0, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(0.0, timer.repeatInterval());
+}
+
+TEST_F(TimerTest, RepeatInterval_OneShotNonZero)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startOneShot(10, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(0.0, timer.repeatInterval());
+}
+
+TEST_F(TimerTest, RepeatInterval_Repeating)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(20, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(20.0, timer.repeatInterval());
+}
+
+TEST_F(TimerTest, AugmentRepeatInterval)
+{
+    Timer<TimerTest> timer((TimerTest*) this, &TimerTest::CountingTask);
+    timer.startRepeating(10, FROM_HERE);
+    EXPECT_FLOAT_EQ(10.0, timer.repeatInterval());
+    EXPECT_FLOAT_EQ(10.0, timer.nextFireInterval());
+
+    AdvanceTimeBy(2.0); // augmentRepeatInterval reposts based off the current time.
+    timer.augmentRepeatInterval(10);
+
+    EXPECT_FLOAT_EQ(20.0, timer.repeatInterval());
+    EXPECT_FLOAT_EQ(20.0, timer.nextFireInterval());
+
+    RunUntilIdleOrDeadlinePassed(m_startTime + 50.0);
+    EXPECT_THAT(m_runTimes, ElementsAre(m_startTime + 22.0, m_startTime + 42.0));
+}
+
+class MockTimerWithAlignment : public TimerBase {
+public:
+    MockTimerWithAlignment() : m_lastFireTime(0.0), m_alignedFireTime(0.0) { }
+
+    virtual void fired() override
+    {
+    }
+
+    double alignedFireTime(double fireTime) const override
+    {
+        m_lastFireTime = fireTime;
+        return m_alignedFireTime;
+    }
+
+    void setAlignedFireTime(double alignedFireTime)
+    {
+        m_alignedFireTime = alignedFireTime;
+    }
+
+    double lastFireTime() const
+    {
+        return m_lastFireTime;
+    }
+
+private:
+    mutable double m_lastFireTime;
+    double m_alignedFireTime;
+};
+
+TEST_F(TimerTest, TimerAlignment_OneShotZero)
+{
+    MockTimerWithAlignment timer;
+    timer.setAlignedFireTime(m_startTime + 1.0);
+
+    timer.start(0.0, 0.0, FROM_HERE);
+
+    // The nextFireInterval gets overrriden.
+    EXPECT_FLOAT_EQ(1.0, timer.nextFireInterval());
+    EXPECT_FLOAT_EQ(0.0, timer.nextUnalignedFireInterval());
+    EXPECT_FLOAT_EQ(m_startTime, timer.lastFireTime());
+}
+
+TEST_F(TimerTest, TimerAlignment_OneShotNonZero)
+{
+    MockTimerWithAlignment timer;
+    timer.setAlignedFireTime(m_startTime + 1.0);
+
+    timer.start(0.5, 0.0, FROM_HERE);
+
+    // The nextFireInterval gets overrriden.
+    EXPECT_FLOAT_EQ(1.0, timer.nextFireInterval());
+    EXPECT_FLOAT_EQ(0.5, timer.nextUnalignedFireInterval());
+    EXPECT_FLOAT_EQ(m_startTime + 0.5, timer.lastFireTime());
+}
+
+TEST_F(TimerTest, DidChangeAlignmentInterval)
+{
+    MockTimerWithAlignment timer;
+    timer.setAlignedFireTime(m_startTime + 1.0);
+
+    timer.start(0.0, 0.0, FROM_HERE);
+
+    EXPECT_FLOAT_EQ(1.0, timer.nextFireInterval());
+    EXPECT_FLOAT_EQ(0.0, timer.nextUnalignedFireInterval());
+    EXPECT_FLOAT_EQ(m_startTime, timer.lastFireTime());
+
+    timer.setAlignedFireTime(m_startTime);
+    timer.didChangeAlignmentInterval(monotonicallyIncreasingTime());
+
+    EXPECT_FLOAT_EQ(0.0, timer.nextFireInterval());
+    EXPECT_FLOAT_EQ(0.0, timer.nextUnalignedFireInterval());
+    EXPECT_FLOAT_EQ(m_startTime, timer.lastFireTime());
+}
+
+
+} // namespace
+} // namespace blink