Remove hit weight experiment

chrome/browser/predictors/autocomplete_action_predictor.cc

Index: chrome/browser/predictors/autocomplete_action_predictor.cc
diff --git a/chrome/browser/predictors/autocomplete_action_predictor.cc b/chrome/browser/predictors/autocomplete_action_predictor.cc
index a64d04fa7f243917b293569cb228ade78e91a553..8a2f65c44785d028b391d4058d195e922ae61e81 100644
--- a/chrome/browser/predictors/autocomplete_action_predictor.cc
+++ b/chrome/browser/predictors/autocomplete_action_predictor.cc
@@ -75,8 +75,6 @@ namespace predictors {
 
 const int AutocompleteActionPredictor::kMaximumDaysToKeepEntry = 14;
 
-double AutocompleteActionPredictor::hit_weight_ = 1.0;
-
 AutocompleteActionPredictor::AutocompleteActionPredictor(Profile* profile)
     : profile_(profile),
       table_(PredictorDatabaseFactory::GetForProfile(
@@ -242,8 +240,7 @@ void AutocompleteActionPredictor::OnOmniboxOpenedUrl(
   const AutocompleteMatch& match = log.result.match_at(log.selected_index);
 
   UMA_HISTOGRAM_BOOLEAN(
-      StringPrintf("Prerender.OmniboxNavigationsCouldPrerender_%.1f%s",

[cbentzel, 2012/05/25 16:34:34]

Do you plan to obsolete these in histograms.xml?

[dominich, 2012/05/25 16:54:57]

Actually I'll remove them if they're even there. They never worked in the UMA UI
as they rely on two field trials which it doesn't support.

-                   get_hit_weight(),
+      StringPrintf("Prerender.OmniboxNavigationsCouldPrerender_%s",
                    prerender::PrerenderManager::GetModeString()).c_str(),
       prerender::IsOmniboxEnabled(profile_));
 
@@ -424,7 +421,7 @@ double AutocompleteActionPredictor::CalculateConfidenceForDbEntry(
   if (value.number_of_hits < kMinimumNumberOfHits)
     return 0.0;
 
-  const double number_of_hits = value.number_of_hits * hit_weight_;
+  const double number_of_hits = static_cast<double>(value.number_of_hits);

[cbentzel, 2012/05/25 16:34:34]

Do you actually need the explicit cast here? Mantissa of double seems like
enough to capture int - although I suppose there is some loss-of-precision if
int is 64 bit on a particular platform.

Either way, I think it's fine, just curious.

[dominich, 2012/05/25 16:54:57]

A preference to be explicit.

const double a = some_int;

could be a mistake. I like to eliminate doubt for the reader.

   return number_of_hits / (number_of_hits + value.number_of_misses);
 }