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 2c8db231b60d3d08be39d6f043cf882cc39f1066..e00e802701919e475cd1d4fe1bbbf387ece7cde9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -23364,8 +23364,11 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <owner>mattm@chromium.org</owner>
   <summary>
     Records the total time it takes for the SafeBrowsing download service to
-    check whether the content of a download is malicious or not. This histogram
-    only includes requests that are sent to the SafeBrowsing server.
+    check whether the content of a download is malicious or not, including file

[Mark P, 2014/05/30 18:31:27]

Thank you for adding clarifications to a pre-existing histogram.  I rarely see
anyone do this.

+    feature extraction, whitelist checking, and server ping. This histogram only
+    includes checks that sent a ping to the SafeBrowsing server. It does not
+    include requests that were cancelled, but does include requests that
+    received a bad response.
   </summary>
 </histogram>
 
@@ -23376,6 +23379,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="SBClientDownload.DownloadRequestNetworkDuration"
+    units="milliseconds">
+  <owner>mattm@chromium.org</owner>
+  <summary>
+    Records the time it takes for the SafeBrowsing download service ping. It
+    includes cancelled and failed pings.

[Mark P, 2014/05/30 18:31:27]

What if you don't get a response.  I would call that a "failed" ping.  What time
do you record?  And what time do you record for cancelled pings?  The time until
cancellation?

[mattm, 2014/06/04 03:18:13]

Failed meant pings that completed but with a bad response. Not getting a
response would be a cancelled ping. Clarified.
Yeah, clarified. Do you think there's a better way to record that?

+  </summary>
+</histogram>
+
 <histogram name="SBClientDownload.DownloadRequestPayloadSize" units="bytes">
   <owner>mattm@chromium.org</owner>
   <summary>
@@ -23391,6 +23403,17 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="SBClientDownload.DownloadRequestTimeoutDuration"
+    units="milliseconds">
+  <owner>mattm@chromium.org</owner>
+  <summary>
+    Records the time it takes for the SafeBrowsing download service to check
+    whether the content of a download is malicious or not, only including the
+    parts that are covered by the timeout.  This histogram includes any checks

[Mark P, 2014/05/30 18:31:27]

Does the "only including..." add something here?  If not, remove it.  If so,
please make be more precise (i.e., what's included and what's excluded).  If you
want to be hand-wavy, at least refer to the relevant code.

[mattm, 2014/06/04 03:18:13]

Done.

+    that started the timeout, regardless if they sent a ping or not.

[Mark P, 2014/05/30 18:31:27]

I don't know what "includes any checks that started the timeout" means.  I would
think a timeout timer could only be started once.  Are you missing a word?

[mattm, 2014/06/04 03:18:13]

Some checks complete before getting to the point that starts the timeout.

+  </summary>
+</histogram>
+
 <histogram name="SBClientDownload.ExtractImageHeadersTime" units="milliseconds">
   <owner>grt@chromium.org</owner>
   <summary>