Loosen FirstMeaningfulPaint UMA network-idle heuristics

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

 // Copyright 2016 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 "core/paint/FirstMeaningfulPaintDetector.h"
 
 #include "core/paint/PaintTiming.h"
 #include "core/testing/DummyPageHolder.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 19 matching lines @@
 
   void simulateLayoutAndPaint(int newElements) {
     StringBuilder builder;
     for (int i = 0; i < newElements; i++)
       builder.append("<span>a</span>");
     document().write(builder.toString());
     document().updateStyleAndLayout();
     detector().notifyPaint();
   }
 
-  void simulateNetworkStable() { detector().networkStableTimerFired(nullptr); }
+  void simulateNetworkStable() {
+    document().setParsingState(Document::FinishedParsing);
+    detector().network0QuietTimerFired(nullptr);
+    detector().network2QuietTimerFired(nullptr);
+  }
+
+  void simulateNetwork0Quiet() {
+    document().setParsingState(Document::FinishedParsing);
+    detector().network0QuietTimerFired(nullptr);
+  }
+
+  void simulateNetwork2Quiet() {
+    document().setParsingState(Document::FinishedParsing);
+    detector().network2QuietTimerFired(nullptr);
+  }
 
  private:
   static double returnMockTime() {
     s_timeElapsed += 1.0;
     return s_timeElapsed;
   }
 
   std::unique_ptr<DummyPageHolder> m_dummyPageHolder;
   TimeFunction m_originalTimeFunction;
   static double s_timeElapsed;
@@ skipping 68 matching lines @@
 TEST_F(FirstMeaningfulPaintDetectorTest,
        FirstMeaningfulPaintShouldNotBeBeforeFirstContentfulPaint) {
   paintTiming().markFirstPaint();
   simulateLayoutAndPaint(10);
   paintTiming().markFirstContentfulPaint();
   simulateNetworkStable();
   EXPECT_GE(paintTiming().firstMeaningfulPaint(),
             paintTiming().firstContentfulPaint());
 }
 
+TEST_F(FirstMeaningfulPaintDetectorTest, Network2QuietThen0Quiet) {
+  paintTiming().markFirstContentfulPaint();
+
+  simulateLayoutAndPaint(1);
+  double afterFirstPaint = monotonicallyIncreasingTime();
+  simulateNetwork2Quiet();
+
+  simulateLayoutAndPaint(10);
+  simulateNetwork0Quiet();
+
+  // The first paint is FirstMeaningfulPaint.
+  EXPECT_GT(paintTiming().firstMeaningfulPaint(), 0.0);
+  EXPECT_LT(paintTiming().firstMeaningfulPaint(), afterFirstPaint);
+}
+
+TEST_F(FirstMeaningfulPaintDetectorTest, Network0QuietThen2Quiet) {
+  paintTiming().markFirstContentfulPaint();
+
+  simulateLayoutAndPaint(1);
+  double afterFirstPaint = monotonicallyIncreasingTime();
+  simulateNetwork0Quiet();
+
+  simulateLayoutAndPaint(10);
+  double afterSecondPaint = monotonicallyIncreasingTime();
+  simulateNetwork2Quiet();
+
+  // The second paint is FirstMeaningfulPaint.
+  EXPECT_GT(paintTiming().firstMeaningfulPaint(), afterFirstPaint);
+  EXPECT_LT(paintTiming().firstMeaningfulPaint(), afterSecondPaint);
+}
+
 }  // namespace blink