Improve FirstMeaningfulPaintDetectorTest's timer tests

This rewrites FirstMeaningfulPaintDetectorTest's test case for the
network quiet timers, using TestingPlatformSupportWithMockScheduler.
Now it verifies that the timers are actually fired.

This also changes other test cases to use mock timer provided by
TestingPlatformSupportWithMockScheduler.

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2755873002
Cr-Commit-Position: refs/heads/master@{#457394}

third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetector.cpp

@@ -19,11 +19,6 @@ namespace {
 // Meaningful Paint.
 const int kBlankCharactersThreshold = 200;
 
-// The page is n-quiet if there are no more than n active network requests for
-// this duration of time.
-const double kNetwork2QuietWindowSeconds = 3;
-const double kNetwork0QuietWindowSeconds = 0.5;
-
 }  // namespace
 
 FirstMeaningfulPaintDetector& FirstMeaningfulPaintDetector::from(

third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetector.h

@@ -53,6 +53,11 @@ class CORE_EXPORT FirstMeaningfulPaintDetector
  private:
   friend class FirstMeaningfulPaintDetectorTest;
 
+  // The page is n-quiet if there are no more than n active network requests for
+  // this duration of time.
+  static constexpr double kNetwork2QuietWindowSeconds = 3;
+  static constexpr double kNetwork0QuietWindowSeconds = 0.5;
+
   Document* document();
   int activeConnections();
   void setNetworkQuietTimers(int activeConnections);

third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp

@@ -6,7 +6,7 @@
 
 #include "core/paint/PaintTiming.h"
 #include "core/testing/DummyPageHolder.h"
-#include "platform/scheduler/test/fake_web_task_runner.h"
+#include "platform/testing/TestingPlatformSupport.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "wtf/text/StringBuilder.h"
 
@@ -15,16 +15,13 @@ namespace blink {
 class FirstMeaningfulPaintDetectorTest : public testing::Test {
  protected:
   void SetUp() override {
+    m_platform->advanceClockSeconds(1);
     m_dummyPageHolder = DummyPageHolder::create(IntSize(800, 600));
-    s_timeElapsed = 0.0;
-    m_originalTimeFunction = setTimeFunctionsForTesting(returnMockTime);
-    m_taskRunner = adoptRef(new scheduler::FakeWebTaskRunner);
-    detector().m_network0QuietTimer.moveToNewTaskRunner(m_taskRunner);
-    detector().m_network2QuietTimer.moveToNewTaskRunner(m_taskRunner);
   }
 
-  void TearDown() override {
-    setTimeFunctionsForTesting(m_originalTimeFunction);
+  double advanceClockAndGetTime() {
+    m_platform->advanceClockSeconds(1);
+    return monotonicallyIncreasingTime();
   }
 
   Document& document() { return m_dummyPageHolder->document(); }
@@ -34,6 +31,7 @@ class FirstMeaningfulPaintDetectorTest : public testing::Test {
   }
 
   void simulateLayoutAndPaint(int newElements) {
+    m_platform->advanceClockSeconds(0.001);
     StringBuilder builder;
     for (int i = 0; i < newElements; i++)
       builder.append("<span>a</span>");
@@ -59,22 +57,7 @@ class FirstMeaningfulPaintDetectorTest : public testing::Test {
   }
 
   void setActiveConnections(int connections) {
-    double time0 = 0.0;
-    double time2 = 0.0;
-    m_taskRunner->setTime(returnMockTime());
-    if (isNetwork0QuietTimerActive())
-      time0 = detector().m_network0QuietTimer.nextFireInterval();
-    if (isNetwork2QuietTimerActive())
-      time2 = detector().m_network2QuietTimer.nextFireInterval();
-
     detector().setNetworkQuietTimers(connections);
-
-    m_0QuietTimerRestarted =
-        isNetwork0QuietTimerActive() &&
-        detector().m_network0QuietTimer.nextFireInterval() != time0;
-    m_2QuietTimerRestarted =
-        isNetwork2QuietTimerActive() &&
-        detector().m_network2QuietTimer.nextFireInterval() != time2;
   }
 
   bool isNetwork0QuietTimerActive() {
@@ -85,25 +68,22 @@ class FirstMeaningfulPaintDetectorTest : public testing::Test {
     return detector().m_network2QuietTimer.isActive();
   }
 
-  bool isNetwork0QuietTimerRestarted() { return m_0QuietTimerRestarted; }
-  bool isNetwork2QuietTimerRestarted() { return m_2QuietTimerRestarted; }
+  bool hadNetwork0Quiet() { return detector().m_network0QuietReached; }
+  bool hadNetwork2Quiet() { return detector().m_network2QuietReached; }
 
- private:
-  static double returnMockTime() {
-    s_timeElapsed += 1.0;
-    return s_timeElapsed;
-  }
+ protected:
+  ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>
+      m_platform;
 
+  static constexpr double kNetwork0QuietWindowSeconds =
+      FirstMeaningfulPaintDetector::kNetwork0QuietWindowSeconds;
+  static constexpr double kNetwork2QuietWindowSeconds =
+      FirstMeaningfulPaintDetector::kNetwork2QuietWindowSeconds;
+
+ private:
   std::unique_ptr<DummyPageHolder> m_dummyPageHolder;
-  RefPtr<scheduler::FakeWebTaskRunner> m_taskRunner;
-  TimeFunction m_originalTimeFunction;
-  bool m_0QuietTimerRestarted;
-  bool m_2QuietTimerRestarted;
-  static double s_timeElapsed;
 };
 
-double FirstMeaningfulPaintDetectorTest::s_timeElapsed;
-
 TEST_F(FirstMeaningfulPaintDetectorTest, NoFirstPaint) {
   simulateLayoutAndPaint(1);
   simulateNetworkStable();
@@ -113,7 +93,7 @@ TEST_F(FirstMeaningfulPaintDetectorTest, NoFirstPaint) {
 TEST_F(FirstMeaningfulPaintDetectorTest, OneLayout) {
   paintTiming().markFirstContentfulPaint();
   simulateLayoutAndPaint(1);
-  double afterPaint = monotonicallyIncreasingTime();
+  double afterPaint = advanceClockAndGetTime();
   EXPECT_EQ(paintTiming().firstMeaningfulPaint(), 0.0);
   simulateNetworkStable();
   EXPECT_GT(paintTiming().firstMeaningfulPaint(), paintTiming().firstPaint());
@@ -123,9 +103,9 @@ TEST_F(FirstMeaningfulPaintDetectorTest, OneLayout) {
 TEST_F(FirstMeaningfulPaintDetectorTest, TwoLayoutsSignificantSecond) {
   paintTiming().markFirstContentfulPaint();
   simulateLayoutAndPaint(1);
-  double afterLayout1 = monotonicallyIncreasingTime();
+  double afterLayout1 = advanceClockAndGetTime();
   simulateLayoutAndPaint(10);
-  double afterLayout2 = monotonicallyIncreasingTime();
+  double afterLayout2 = advanceClockAndGetTime();
   simulateNetworkStable();
   EXPECT_GT(paintTiming().firstMeaningfulPaint(), afterLayout1);
   EXPECT_LT(paintTiming().firstMeaningfulPaint(), afterLayout2);
@@ -134,7 +114,7 @@ TEST_F(FirstMeaningfulPaintDetectorTest, TwoLayoutsSignificantSecond) {
 TEST_F(FirstMeaningfulPaintDetectorTest, TwoLayoutsSignificantFirst) {
   paintTiming().markFirstContentfulPaint();
   simulateLayoutAndPaint(10);
-  double afterLayout1 = monotonicallyIncreasingTime();
+  double afterLayout1 = advanceClockAndGetTime();
   simulateLayoutAndPaint(1);
   simulateNetworkStable();
   EXPECT_GT(paintTiming().firstMeaningfulPaint(), paintTiming().firstPaint());
@@ -145,7 +125,7 @@ TEST_F(FirstMeaningfulPaintDetectorTest, FirstMeaningfulPaintCandidate) {
   paintTiming().markFirstContentfulPaint();
   EXPECT_EQ(paintTiming().firstMeaningfulPaintCandidate(), 0.0);
   simulateLayoutAndPaint(1);
-  double afterPaint = monotonicallyIncreasingTime();
+  double afterPaint = advanceClockAndGetTime();
   // The first candidate gets ignored.
   EXPECT_EQ(paintTiming().firstMeaningfulPaintCandidate(), 0.0);
   simulateLayoutAndPaint(10);
@@ -161,7 +141,7 @@ TEST_F(FirstMeaningfulPaintDetectorTest,
        OnlyOneFirstMeaningfulPaintCandidateBeforeNetworkStable) {
   paintTiming().markFirstContentfulPaint();
   EXPECT_EQ(paintTiming().firstMeaningfulPaintCandidate(), 0.0);
-  double beforePaint = monotonicallyIncreasingTime();
+  double beforePaint = advanceClockAndGetTime();
   simulateLayoutAndPaint(1);
   // The first candidate is initially ignored.
   EXPECT_EQ(paintTiming().firstMeaningfulPaintCandidate(), 0.0);
@@ -199,7 +179,7 @@ TEST_F(FirstMeaningfulPaintDetectorTest, Network2QuietThen0Quiet) {
   paintTiming().markFirstContentfulPaint();
 
   simulateLayoutAndPaint(1);
-  double afterFirstPaint = monotonicallyIncreasingTime();
+  double afterFirstPaint = advanceClockAndGetTime();
   simulateNetwork2Quiet();
 
   simulateLayoutAndPaint(10);
@@ -214,11 +194,11 @@ TEST_F(FirstMeaningfulPaintDetectorTest, Network0QuietThen2Quiet) {
   paintTiming().markFirstContentfulPaint();
 
   simulateLayoutAndPaint(1);
-  double afterFirstPaint = monotonicallyIncreasingTime();
+  double afterFirstPaint = advanceClockAndGetTime();
   simulateNetwork0Quiet();
 
   simulateLayoutAndPaint(10);
-  double afterSecondPaint = monotonicallyIncreasingTime();
+  double afterSecondPaint = advanceClockAndGetTime();
   simulateNetwork2Quiet();
 
   // The second paint is FirstMeaningfulPaint.
@@ -226,33 +206,45 @@ TEST_F(FirstMeaningfulPaintDetectorTest, Network0QuietThen2Quiet) {
   EXPECT_LT(paintTiming().firstMeaningfulPaint(), afterSecondPaint);
 }
 
-TEST_F(FirstMeaningfulPaintDetectorTest, NetworkQuietTimers) {
-  setActiveConnections(3);
-  EXPECT_FALSE(isNetwork0QuietTimerActive());
-  EXPECT_FALSE(isNetwork2QuietTimerActive());
-
-  setActiveConnections(2);
-  EXPECT_FALSE(isNetwork0QuietTimerActive());
-  EXPECT_TRUE(isNetwork2QuietTimerActive());
+TEST_F(FirstMeaningfulPaintDetectorTest, Network0QuietTimer) {
+  paintTiming().markFirstContentfulPaint();
 
   setActiveConnections(1);
   EXPECT_FALSE(isNetwork0QuietTimerActive());
-  EXPECT_TRUE(isNetwork2QuietTimerActive());
-  EXPECT_FALSE(isNetwork2QuietTimerRestarted());
-
-  setActiveConnections(2);
-  EXPECT_TRUE(isNetwork2QuietTimerRestarted());
 
   setActiveConnections(0);
+  m_platform->runForPeriodSeconds(kNetwork0QuietWindowSeconds - 0.1);
   EXPECT_TRUE(isNetwork0QuietTimerActive());
-  EXPECT_TRUE(isNetwork2QuietTimerActive());
-  EXPECT_FALSE(isNetwork2QuietTimerRestarted());
+  EXPECT_FALSE(hadNetwork0Quiet());
 
-  setActiveConnections(0);
+  setActiveConnections(0);  // This should reset the 0-quiet timer.
+  m_platform->runForPeriodSeconds(kNetwork0QuietWindowSeconds - 0.1);
   EXPECT_TRUE(isNetwork0QuietTimerActive());
-  EXPECT_TRUE(isNetwork0QuietTimerRestarted());
+  EXPECT_FALSE(hadNetwork0Quiet());
+
+  m_platform->runForPeriodSeconds(0.1001);
+  EXPECT_TRUE(hadNetwork0Quiet());
+}
+
+TEST_F(FirstMeaningfulPaintDetectorTest, Network2QuietTimer) {
+  paintTiming().markFirstContentfulPaint();
+
+  setActiveConnections(3);
+  EXPECT_FALSE(isNetwork2QuietTimerActive());
+
+  setActiveConnections(2);
+  m_platform->runForPeriodSeconds(kNetwork2QuietWindowSeconds - 0.1);
+  EXPECT_TRUE(isNetwork2QuietTimerActive());
+  EXPECT_FALSE(hadNetwork2Quiet());
+
+  setActiveConnections(2);  // This should reset the 2-quiet timer.
+  m_platform->runForPeriodSeconds(kNetwork2QuietWindowSeconds - 0.1);
   EXPECT_TRUE(isNetwork2QuietTimerActive());
-  EXPECT_FALSE(isNetwork2QuietTimerRestarted());
+  EXPECT_FALSE(hadNetwork2Quiet());
+
+  setActiveConnections(1);  // This should not reset the 2-quiet timer.
+  m_platform->runForPeriodSeconds(0.1001);
+  EXPECT_TRUE(hadNetwork2Quiet());
 }
 
 }  // namespace blink