Remove hit weight experiment.

Results of the experiment show that higher hit weights yield greater coverage, but at the expense of accuracy. The decreased accuracy outweighs the increased coverage.

BUG=111069


Review URL: https://chromiumcodereview.appspot.com/10453013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@139086 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 3 insertions, 28 deletions

diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index 228c6cd..43c71f6 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -200,26 +200,6 @@ void ConfigureOmniboxPrerender() {
           2012, 12, 30, &g_omnibox_trial_default_group_number));
   omnibox_prerender_trial->AppendGroup("OmniboxPrerenderDisabled",
                                        kDisabledProbability);
-
-  // Field trial to set weighting of hits.
-  const base::FieldTrial::Probability kFourProbability = 33;
-  const base::FieldTrial::Probability kEightProbability = 33;
-
-  scoped_refptr<base::FieldTrial> weighting_trial(
-      base::FieldTrialList::FactoryGetFieldTrial(
-          "OmniboxPrerenderHitWeightingTrial", kDivisor,
-          "OmniboxPrerenderWeight1.0", 2012, 8, 30, NULL));
-  const int kOmniboxWeightFourGroup =
-      weighting_trial->AppendGroup("OmniboxPrerenderWeight4.0",
-                                   kFourProbability);
-  const int kOmniboxWeightEightGroup =
-      weighting_trial->AppendGroup("OmniboxPrerenderWeight8.0",
-                                   kEightProbability);
-  const int group = weighting_trial->group();
-  if (group == kOmniboxWeightFourGroup)
-    predictors::AutocompleteActionPredictor::set_hit_weight(4.0);
-  else if (group == kOmniboxWeightEightGroup)
-    predictors::AutocompleteActionPredictor::set_hit_weight(8.0);
 }
 
 bool IsOmniboxEnabled(Profile* profile) {
diff --git a/chrome/browser/prerender/prerender_histograms.cc b/chrome/browser/prerender/prerender_histograms.cc
index f150608..19b62c7 100644
--- a/chrome/browser/prerender/prerender_histograms.cc
+++ b/chrome/browser/prerender/prerender_histograms.cc
@@ -48,10 +48,7 @@ std::string GetHistogramName(Origin origin, uint8 experiment_id,
 
   switch (origin) {
     case ORIGIN_OMNIBOX:
-      return ComposeHistogramName(
-          StringPrintf("omnibox_%.1f",
-                       AutocompleteActionPredictor::get_hit_weight()).c_str(),
-          name);
+      return ComposeHistogramName("omnibox", name);
     case ORIGIN_LINK_REL_PRERENDER:
       return ComposeHistogramName("web", name);
     case ORIGIN_GWS_PRERENDER:  // Handled above.
@@ -154,8 +151,7 @@ void PrerenderHistograms::RecordPrerender(Origin origin, const GURL& url) {
 void PrerenderHistograms::RecordPrerenderStarted(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
     UMA_HISTOGRAM_COUNTS(
-        StringPrintf("Prerender.OmniboxPrerenderCount_%.1f%s",
-                     AutocompleteActionPredictor::get_hit_weight(),
+        StringPrintf("Prerender.OmniboxPrerenderCount_%s",
                      PrerenderManager::GetModeString()).c_str(),
         1);
   }
@@ -164,8 +160,7 @@ void PrerenderHistograms::RecordPrerenderStarted(Origin origin) const {
 void PrerenderHistograms::RecordUsedPrerender(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
     UMA_HISTOGRAM_COUNTS(
-        StringPrintf("Prerender.OmniboxNavigationsUsedPrerenderCount_%.1f%s",
-                     AutocompleteActionPredictor::get_hit_weight(),
+        StringPrintf("Prerender.OmniboxNavigationsUsedPrerenderCount_%s",
                      PrerenderManager::GetModeString()).c_str(),
         1);
   }