Remove hit weight experiment

chrome/browser/predictors/autocomplete_action_predictor.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/predictors/autocomplete_action_predictor.h"
 
 #include <math.h>
 
 #include <vector>
 
@@ skipping 57 matching lines @@
       return false;
   }
 }
 
 }  // namespace
 
 namespace predictors {
 
 const int AutocompleteActionPredictor::kMaximumDaysToKeepEntry = 14;
 
-double AutocompleteActionPredictor::hit_weight_ = 1.0;
-
 AutocompleteActionPredictor::AutocompleteActionPredictor(Profile* profile)
     : profile_(profile),
       table_(PredictorDatabaseFactory::GetForProfile(
           profile)->autocomplete_table()),
       initialized_(false) {
   // Request the in-memory database from the history to force it to load so it's
   // available as soon as possible.
   HistoryService* history_service =
       profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   if (history_service)
@@ skipping 145 matching lines @@
 }
 
 void AutocompleteActionPredictor::OnOmniboxOpenedUrl(
     const AutocompleteLog& log) {
   if (log.text.length() < kMinimumUserTextLength)
     return;
 
   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_));
 
   const GURL& opened_url = match.destination_url;
 
   // If the Omnibox triggered a prerender but the URL doesn't match the one the
   // user is navigating to, cancel the prerender.
   prerender::PrerenderManager* prerender_manager =
       prerender::PrerenderManagerFactory::GetForProfile(profile_);
   // |prerender_manager| can be NULL in incognito mode or if prerendering is
@@ skipping 160 matching lines @@
   *is_in_db = true;
   return CalculateConfidenceForDbEntry(iter);
 }
 
 double AutocompleteActionPredictor::CalculateConfidenceForDbEntry(
     DBCacheMap::const_iterator iter) const {
   const DBCacheValue& value = iter->second;
   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);
 }
 
 void AutocompleteActionPredictor::AddAndUpdateRows(
     const AutocompleteActionPredictorTable::Rows& rows_to_add,
     const AutocompleteActionPredictorTable::Rows& rows_to_update) {
   if (!initialized_)
     return;
 
   for (AutocompleteActionPredictorTable::Rows::const_iterator it =
@@ skipping 69 matching lines @@
                             DATABASE_ACTION_DELETE_SOME, DATABASE_ACTION_COUNT);
 }
 
 AutocompleteActionPredictor::TransitionalMatch::TransitionalMatch() {
 }
 
 AutocompleteActionPredictor::TransitionalMatch::~TransitionalMatch() {
 }
 
 }  // namespace predictors