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 a868c97bf2d2ffcd0546c06391f894fec0080672..e2fd9efb10f5d14124933eaedcfc9294813f343c 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -10466,6 +10466,25 @@ 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>