[NoStatePrefetch] Add performance histograms.

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 438c1764ec4c1ad4fcadb9f6718dc3d3bf6ad79a..4998bf611b2e7a17054b6e04ce909f4f0e6c79e3 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -45578,6 +45578,13 @@ 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>
@@ -45612,6 +45619,74 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </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.NoStatePrefetchTTFCPWithoutRevalidationCacheable"
+    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
+    cacheable.
+  </summary>
+</histogram>
+
+<histogram name="Prerender.NoStatePrefetchTTFCPWithoutRevalidationNoStore"
+    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.NoStatePrefetchTTFCPWithRevalidationCacheable"
+    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.NoStatePrefetchTTFCPWithRevalidationNoStore"
+    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.OmniboxNavigationsCouldPrerender">
   <owner>pasko@chromium.org</owner>
   <summary>
@@ -104149,9 +104224,20 @@ 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.NoStatePrefetchTTFCPReferenceCacheable"/>
+  <affected-histogram name="Prerender.NoStatePrefetchTTFCPReferenceNoStore"/>
+  <affected-histogram
+      name="Prerender.NoStatePrefetchTTFCPWithoutRevalidationCacheable"/>
+  <affected-histogram
+      name="Prerender.NoStatePrefetchTTFCPWithoutRevalidationNoStore"/>
+  <affected-histogram
+      name="Prerender.NoStatePrefetchTTFCPWithRevalidationCacheable"/>
+  <affected-histogram
+      name="Prerender.NoStatePrefetchTTFCPWithRevalidationNoStore"/>
   <affected-histogram name="Prerender.PageVisitedStatus"/>
   <affected-histogram name="Prerender.PerceivedPLT"/>
   <affected-histogram name="Prerender.PerceivedPLTFirstAfterMiss"/>