Loosen FirstMeaningfulPaint UMA network-idle heuristics

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

Index: third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp
diff --git a/third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp b/third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp
index 842d2731b0604d96e2da5a3b072ac73c9e1196ee..1beeb38678b1b6dac1e16515a3e22702eac001f7 100644
--- a/third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp
+++ b/third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetectorTest.cpp
@@ -37,7 +37,21 @@ class FirstMeaningfulPaintDetectorTest : public testing::Test {
     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() {
@@ -126,4 +140,35 @@ TEST_F(FirstMeaningfulPaintDetectorTest,
             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