[Prerender] first contentful paint histograms.

chrome/browser/prerender/prerender_histograms.cc

Index: chrome/browser/prerender/prerender_histograms.cc
diff --git a/chrome/browser/prerender/prerender_histograms.cc b/chrome/browser/prerender/prerender_histograms.cc
index 4e97663049a8d3e75b14b55e98a28ec60af7f2cc..398be3fb96ed06a6cc0619b29fc52bfbb55fac3d 100644
--- a/chrome/browser/prerender/prerender_histograms.cc
+++ b/chrome/browser/prerender/prerender_histograms.cc
@@ -310,6 +310,16 @@ void PrerenderHistograms::RecordPerceivedPageLoadTime(
   }
 }
 
+void PrerenderHistograms::RecordPerceivedFirstContentfulPaintStatus(
+    Origin origin,
+    bool successful,
+    bool was_hidden) {
+  RecordHistogramEnum(
+      GetHistogramName(origin, IsOriginWash(), "PerceivedTTFCPRecorded") +

[pasko, 2016/12/12 17:32:06]

this suffix is not mentioned in histograms.xml

[mattcary, 2016/12/12 21:14:54]

Oops, done.

What happens if the histogram is missing in histograms.xml? This should have
been generated by the tests, and nothing failed---it seems like a bug that
histograms.xml isn't validated.

[pasko, 2016/12/15 19:37:51]

Yeah, I guess we could get some histograms verified against histograms.xml in
debug mode, but it was not ever done afaict. So defining metrics that we rely on
to make major decisions is like shooting in the dark.

+          FirstContentfulPaintHiddenName(was_hidden),
+      successful ? 1 : 0, 2);
+}
+
 void PrerenderHistograms::RecordPageLoadTimeNotSwappedIn(
     Origin origin,
     base::TimeDelta page_load_time,
@@ -452,24 +462,38 @@ void PrerenderHistograms::RecordPrefetchRedirectCount(
   RecordHistogramEnum(histogram_name, redirect_count, kMaxRedirectCount);
 }
 
-void PrerenderHistograms::RecordFirstContentfulPaint(
+void PrerenderHistograms::RecordPrefetchFirstContentfulPaintTime(
     Origin origin,
     bool is_no_store,
+    bool was_hidden,
     base::TimeDelta time,
     base::TimeDelta prefetch_age) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!prefetch_age.is_zero()) {
     DCHECK_NE(origin, ORIGIN_NONE);
-    RecordHistogramTime(GetHistogramName(origin, IsOriginWash(),
-                                         "Prerender.NoStatePrefetchAge"),
-                        base::TimeDelta::FromMilliseconds(10),
-                        base::TimeDelta::FromMinutes(30), prefetch_age, 50);
+    RecordHistogramTime(
+        GetHistogramName(origin, IsOriginWash(), "Prerender.PrefetchAge"),
+        base::TimeDelta::FromMilliseconds(10), base::TimeDelta::FromMinutes(30),
+        prefetch_age, 50);
   }
 
-  RecordHistogramTime(GetFirstContentfulPaintHistogramName(
-                          origin, IsOriginWash(), is_no_store, prefetch_age),
-                      base::TimeDelta::FromMilliseconds(10),
+  std::string histogram_base_name;
+  if (prefetch_age.is_zero()) {
+    histogram_base_name = "PrefetchTTFCP.Reference";
+  } else {
+    histogram_base_name = prefetch_age < base::TimeDelta::FromMinutes(
+                                             net::HttpCache::kPrefetchReuseMins)
+                              ? "PrefetchTTFCP.Warm"
+                              : "PrefetchTTFCP.Cold";
+  }
+
+  histogram_base_name += is_no_store ? ".NoStore" : ".Cacheable";
+  histogram_base_name += FirstContentfulPaintHiddenName(was_hidden);
+  std::string histogram_name =
+      GetHistogramName(origin, IsOriginWash(), histogram_base_name);
+
+  RecordHistogramTime(histogram_name, base::TimeDelta::FromMilliseconds(10),
                       base::TimeDelta::FromMinutes(2), time, 50);
 }
 
@@ -479,24 +503,9 @@ bool PrerenderHistograms::IsOriginWash() const {
   return origin_wash_;
 }
 
-// static
-std::string PrerenderHistograms::GetFirstContentfulPaintHistogramName(
-    Origin origin,
-    bool is_wash,
-    bool is_no_store,
-    base::TimeDelta prefetch_age) {
-  std::string histogram_base_name;
-  if (prefetch_age.is_zero()) {
-    histogram_base_name = "NoStatePrefetchTTFCP.Reference";
-  } else {
-    histogram_base_name = prefetch_age < base::TimeDelta::FromMinutes(
-                                             net::HttpCache::kPrefetchReuseMins)
-                              ? "NoStatePrefetchTTFCP.Warm"
-                              : "NoStatePrefetchTTFCP.Cold";
-  }
-
-  histogram_base_name += is_no_store ? ".NoStore" : ".Cacheable";
-  return GetHistogramName(origin, is_wash, histogram_base_name);
+std::string PrerenderHistograms::FirstContentfulPaintHiddenName(
+    bool was_hidden) {
+  return was_hidden ? ".Hidden" : ".Visible";
 }
 
 }  // namespace prerender