Make a separate histogram for MatchComplete Final Status'es and

chrome/browser/prerender/prerender_histograms.cc

Index: chrome/browser/prerender/prerender_histograms.cc
===================================================================
--- chrome/browser/prerender/prerender_histograms.cc	(revision 118385)
+++ chrome/browser/prerender/prerender_histograms.cc	(working copy)
@@ -169,6 +169,26 @@
         100)); \
 }
 
+// Summary of all histograms Perceived PLT histograms:

[cbentzel, 2012/01/24 14:55:46]

Thanks for adding this description, it's very helpful.

[tburkard, 2012/01/24 19:15:54]

Done.

+// (all prefixed PerceivedPLT)
+// PerceivedPLT -- Perceived Pageloadtimes (PPLT) for all pages in the group.
+// ...Windowed -- PPLT for pages in the 30s after a prerender.

[cbentzel, 2012/01/24 14:55:46]

Nit: after a prerender is created?

[tburkard, 2012/01/24 19:15:54]

Done.

+// ...Matched -- A prerendered page that was swapped in.

[cbentzel, 2012/01/24 14:55:46]

Nit: perhaps this should discuss how this is recorded for the Control and NoUse
case, since neither swap in. 

[tburkard, 2012/01/24 19:15:54]

Done.

+// ...MatchedComplete -- A prerendered page that was swapped in + a few
+// that were not swapped in so that the set of pages lines up more closely with
+// the control group.
+// ...FirstAfterMiss -- First page to finish loading after a prerender, which
+// is different from the page that was prerendered.
+// ...FirstAfterMissNonOverlapping -- Same as FirstAfterMiss, but only
+// triggering for the first page to finish after the prerender that also started
+// after the prerender started.
+// ...FirstAfterMissBoth -- pages meeting
+// FirstAfterMiss AND FirstAfterMissNonOverlapping
+// ...FirstAfterMissAnyOnly -- pages meeting
+// FirstAfterMiss but NOT FirstAfterMissNonOverlapping
+// ..FirstAfterMissNonOverlappingOnly -- pages meeting
+// FirstAfterMissNonOverlapping but NOT FirstAfterMiss
+
 void PrerenderHistograms::RecordPerceivedPageLoadTime(
     base::TimeDelta perceived_page_load_time, bool was_prerender,
     bool was_complete_prerender, const GURL& url) {
@@ -256,14 +276,24 @@
       UMA_HISTOGRAM_TIMES(name, time));
 }
 
-void PrerenderHistograms::RecordFinalStatus(Origin origin,
-                                            uint8 experiment_id,
-                                            FinalStatus final_status) const {
+void PrerenderHistograms::RecordFinalStatus(
+    Origin origin,
+    uint8 experiment_id,
+    PrerenderContents::MatchCompleteStatus mc_status,
+    FinalStatus final_status) const {
   DCHECK(final_status != FINAL_STATUS_MAX);
-  PREFIXED_HISTOGRAM_ORIGIN_EXPERIMENT(
-      base::FieldTrial::MakeName("FinalStatus", "Prerender"),
-      origin, experiment_id,
-      UMA_HISTOGRAM_ENUMERATION(name, final_status, FINAL_STATUS_MAX));
+  if (mc_status != PrerenderContents::MATCH_COMPLETE_REPLACEMENT) {

[cbentzel, 2012/01/24 14:55:46]

Do you want this to get triggered when mc_status == MATCH_COMPLETE_REPLACED?

[tburkard, 2012/01/24 19:15:54]

No, also in the MATCH_COMPLETE_DEFAULT case.
The MC default case means no special treatment, so it becomes part of both
FinalStatus and FinalStatusMatchComplete.

Only when you have 2 instances (one for the actual perender and one dummy) do
you have to account one in one histogram and the other in the other histogram.

Added a comment explaining this.

On 2012/01/24 14:55:46, cbentzel wrote:

+    PREFIXED_HISTOGRAM_ORIGIN_EXPERIMENT(
+        base::FieldTrial::MakeName("FinalStatus", "Prerender"),
+        origin, experiment_id,
+        UMA_HISTOGRAM_ENUMERATION(name, final_status, FINAL_STATUS_MAX));
+  }
+  if (mc_status != PrerenderContents::MATCH_COMPLETE_REPLACED) {
+    PREFIXED_HISTOGRAM_ORIGIN_EXPERIMENT(
+        base::FieldTrial::MakeName("FinalStatusMatchComplete", "Prerender"),
+        origin, experiment_id,
+        UMA_HISTOGRAM_ENUMERATION(name, final_status, FINAL_STATUS_MAX));
+  }
 }
 
 uint8 PrerenderHistograms::GetCurrentExperimentId() const {