Expose packet loss counts from QUIC to NetworkQualityEstimator

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index ac36d312131f86bd5b37b11d6c6f6ca361e3ef6e..c2bf1c66163c0c04c1c01a6d36ffe44669eaa112 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -31075,6 +31075,19 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="NQE.PacketLossRate" units="100 times">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Rough estimate of the packet loss rate multiplied by 100, before a
+    connectivity change is detected.
+
+    This metric is recorded when a connectivity change is detected. This will
+    miss data from users whose connection type never changes and will be biased
+    to users whose connection type changes frequently.
+  </summary>
+</histogram>
+
 <histogram name="NQE.PeakKbps" units="Kbps">
   <owner>bengr@chromium.org</owner>
   <owner>tbansal@chromium.org</owner>
@@ -85399,6 +85412,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="NQE.DifferenceRTTActualAndEstimated"/>
   <affected-histogram name="NQE.DifferenceRTTEstimatedAndActual"/>
   <affected-histogram name="NQE.FastestRTT"/>
+  <affected-histogram name="NQE.PacketLossRate"/>
   <affected-histogram name="NQE.PeakKbps"/>
   <affected-histogram name="NQE.RatioEstimatedToActualRTT"/>
   <affected-histogram name="NQE.RTT.Percentile0"/>