debug first paint in iframe

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 65940300c13a52fb12ba2fea3210ac24c0417ded..3155b3f34e86e9f25e58c85825c2f2f29dc64d34 100644
--- a/third_party/WebKit/Source/core/paint/PaintTiming.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintTiming.cpp
@@ -104,6 +104,8 @@ void PaintTiming::setFirstMeaningfulPaint(double stamp) {
 void PaintTiming::notifyPaint(bool isFirstPaint,
                               bool textPainted,
                               bool imagePainted) {
+  fprintf(stderr, "%s\n", "notifyPaint");
+  fprintf(stderr, "%s\n", supplementable()->url().getString().ascii().data());
   if (isFirstPaint)
     markFirstPaint();
   if (textPainted)