Ensure the scheduler always changes from UseCase LOADING to NONE.

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

Index: third_party/WebKit/Source/core/paint/PaintTiming.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintTiming.cpp b/third_party/WebKit/Source/core/paint/PaintTiming.cpp
index 60923e0ce23c35760391ffefe1433cd337e56add..65940300c13a52fb12ba2fea3210ac24c0417ded 100644
--- a/third_party/WebKit/Source/core/paint/PaintTiming.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintTiming.cpp
@@ -83,10 +83,10 @@ void PaintTiming::markFirstImagePaint() {
   notifyPaintTimingChanged();
 }
 
-void PaintTiming::markFirstMeaningfulPaintCandidate() {
+void PaintTiming::setFirstMeaningfulPaintCandidate(double timestamp) {
   if (m_firstMeaningfulPaintCandidate)
     return;
-  m_firstMeaningfulPaintCandidate = monotonicallyIncreasingTime();
+  m_firstMeaningfulPaintCandidate = timestamp;
   if (frame() && frame()->view() && !frame()->view()->parent()) {
     frame()->frameScheduler()->onFirstMeaningfulPaint();
   }