Record data use of favicon

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 af76124e3f2389866917674958835fb385c08e5d..276660a51b070201f8b881c62dec151a2a44e311 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -10661,6 +10661,25 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="DataUse.FavIcon.Downstream" units="bytes">
+  <owner>rajendrant@chromium.org</owner>
+  <owner>bengr@chromium.org</owner>
+  <summary>
+    Records the downstream network data use of favicon requests. Logged when the
+    request is completed or redirected. Zero bytes are recorded when the request
+    is served from cache.
+  </summary>
+</histogram>
+
+<histogram name="DataUse.FavIcon.Downstream.Non200Response" units="bytes">
+  <owner>rajendrant@chromium.org</owner>
+  <owner>bengr@chromium.org</owner>
+  <summary>
+    Records the downstream network data use of favicon requests with non 200
+    response code. Logged when the request is completed or redirected.
+  </summary>
+</histogram>
+
 <histogram name="DataUse.MessageSize" units="bytes">
   <owner>amohammadkhan@chromium.org</owner>
   <owner>bengr@chromium.org</owner>