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 2972cf895dc880916baa6fbf0ac19f056c550506..d0014b0663210a14c3e9c996c1db4a8b56bfede6 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -45870,6 +45870,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Prerender.NoStatePrefetchAge" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>Time between the prefetch and the actual load of the page.</summary>
+</histogram>
+
 <histogram name="Prerender.NoStatePrefetchMainResourceRedirects"
     units="redirects">
   <owner>droger@chromium.org</owner>
@@ -45904,6 +45911,70 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Prerender.NoStatePrefetchTTFCPColdCacheable" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were not prefetched recently
+    enough to skip the revalidation checks, and where the main resource is
+    cacheable.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPColdNoStore" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were not prefetched recently
+    enough to skip the revalidation checks, and where the main resource is
+    &quot;no-store&quot;.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPReferenceCacheable" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were not prefetched and where
+    the main resource is cacheable.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPReferenceNoStore" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were not prefetched and where
+    the main resource is &quot;no-store&quot;.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPWarmCacheable" units="ms">

[Alexei Svitkine (slow), 2016/09/15 16:53:28]

I suggest using the histogram_suffixes construct to make the XML a bit more
concise. See the top of the file for an example.

Also suggest adding an intermediate . as a delimiter to make these a bit more
readable, e.g.:

rerender.NoStatePrefetchTTFCP.WarmCacheable

[droger, 2016/09/16 12:21:50]

I added the dot separator.

However, I don't know if the suffix thing is possible, since these histograms
already have a suffix.
Can we do nested <suffix> constructs?
Or should I do second suffix construct, and list all the combinations from the
first suffix construct in the <affected-histograms>?

[Alexei Svitkine (slow), 2016/09/16 14:16:21]

You can do multiple sets of suffixes and affected histograms can list suffixed
entries that were created by a different suffixes definition.

[droger, 2016/09/16 14:51:58]

Done.
Does this break if the suffix definition are re-ordered in the future?

[Alexei Svitkine (slow), 2016/09/16 14:59:36]

Nope - re-ordering suffixes is fine.

+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were prefetched recently
+    enough to skip the revalidation checks, and where the main resource is
+    cacheable.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPWarmNoStore" units="ms">
+  <owner>droger@chromium.org</owner>
+  <owner>mattcary@chromium.org</owner>
+  <owner>pasko@chromium.org</owner>
+  <summary>
+    Time to first contentful paint for pages that were prefetched recently
+    enough to skip the revalidation checks, and where the main resource is
+    &quot;no-store&quot;.
+  </summary>
+</histogram>
+
 <histogram name="Prerender.OmniboxNavigationsCouldPrerender">
   <owner>pasko@chromium.org</owner>
   <summary>
@@ -104701,9 +104772,16 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Prerender.LocalPredictorTimeUntilUsed"/>
   <affected-histogram name="Prerender.NetworkBytesUsed"/>
   <affected-histogram name="Prerender.NetworkBytesWasted"/>
+  <affected-histogram name="Prerender.NoStatePrefetchAge"/>
   <affected-histogram name="Prerender.NoStatePrefetchMainResourceRedirects"/>
   <affected-histogram name="Prerender.NoStatePrefetchResponseTypes"/>
   <affected-histogram name="Prerender.NoStatePrefetchSubResourceRedirects"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPColdCacheable"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPColdNoStore"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPReferenceCacheable"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPReferenceNoStore"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPWarmCacheable"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPWarmNoStore"/>
   <affected-histogram name="Prerender.PageVisitedStatus"/>
   <affected-histogram name="Prerender.PerceivedPLT"/>
   <affected-histogram name="Prerender.PerceivedPLTFirstAfterMiss"/>