Add Precache.Fetch.ResponseBytes.Daily.

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 c5f0beb67b77a9fadc14f5d2a03ba4a56cd14aa1..976cffeb9a173a5f22ecf884529e8751f124f3a7 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -51598,6 +51598,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Precache.Fetch.ResponseBytes.Daily" units="bytes">
+  <owner>twifkak@chromium.org</owner>
+  <summary>
+    The total number of response bytes in 24 hours received over the network
+    from all prefetch requests, including config, manifests, and resources.
+    Logged during the next precache run after the 24 hours has elapsed.
+  </summary>
+</histogram>
+
 <histogram name="Precache.Fetch.ResponseBytes.Network" units="bytes">
   <owner>twifkak@chromium.org</owner>
   <owner>bengr@chromium.org</owner>