Adding a fourth omnibox prerender experiment.

chrome/browser/prerender/prerender_field_trial.cc

 // Copyright (c) 2011 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/prerender/prerender_field_trial.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 namespace prerender {
 
 namespace {
 
 int omnibox_original_group_id = 0;
 int omnibox_conservative_group_id = 0;
 int omnibox_exact_group_id = 0;
+int omnibox_exact_full_group_id = 0;
 
 const char* kOmniboxHeuristicNames[] = {
   "Original",
   "Conservative",
-  "Exact"
+  "Exact",
+  "Exact_Full"
 };
 COMPILE_ASSERT(arraysize(kOmniboxHeuristicNames) == OMNIBOX_HEURISTIC_MAX,
                OmniboxHeuristic_name_count_mismatch);
 
+const char kPrerenderFromOmniboxTrialName[] = "PrerenderFromOmnibox";
+const char kPrerenderFromOmniboxHeuristicTrialName[] =
+    "PrerenderFromOmniboxHeuristic";
+
 const char* NameFromOmniboxHeuristic(OmniboxHeuristic heuristic) {
   DCHECK_LT(static_cast<unsigned int>(heuristic),
             arraysize(kOmniboxHeuristicNames));
   return kOmniboxHeuristicNames[heuristic];
 }
 
 }  // end namespace
 
 void ConfigurePrerenderFromOmnibox();
 
@@ skipping 115 matching lines @@
 
   ConfigurePrerenderFromOmnibox();
 }
 
 void ConfigurePrerenderFromOmnibox() {
   // Field trial to see if we're enabled.
   const base::FieldTrial::Probability kDivisor = 100;
 
   const base::FieldTrial::Probability kEnabledProbability = 40;
   scoped_refptr<base::FieldTrial> enabled_trial(
-      new base::FieldTrial("PrerenderFromOmnibox", kDivisor,
+      new base::FieldTrial(kPrerenderFromOmniboxTrialName, kDivisor,
                            "OmniboxPrerenderDisabled", 2012, 8, 30));
   enabled_trial->AppendGroup("OmniboxPrerenderEnabled", kEnabledProbability);
 
   // Field trial to see which heuristic to use.
-  const base::FieldTrial::Probability kConservativeProbability = 33;
-  const base::FieldTrial::Probability kExactProbability = 33;
+  const base::FieldTrial::Probability kConservativeProbability = 25;
+  const base::FieldTrial::Probability kExactProbability = 25;
+  const base::FieldTrial::Probability kExactFullProbability = 25;
   scoped_refptr<base::FieldTrial> heuristic_trial(
-      new base::FieldTrial("PrerenderFromOmniboxHeuristic", kDivisor,
+      new base::FieldTrial(kPrerenderFromOmniboxHeuristicTrialName, kDivisor,
                            "OriginalAlgorithm", 2012, 8, 30));
   omnibox_original_group_id = base::FieldTrial::kDefaultGroupNumber;
   omnibox_conservative_group_id =
       heuristic_trial->AppendGroup("ConservativeAlgorithm",
                                    kConservativeProbability);
   omnibox_exact_group_id =
       heuristic_trial->AppendGroup("ExactAlgorithm", kExactProbability);
+  omnibox_exact_full_group_id =
+      heuristic_trial->AppendGroup("ExactFullAlgorithm", kExactFullProbability);
 }
 
 bool IsOmniboxEnabled(Profile* profile) {
   if (!profile || profile->IsOffTheRecord())
     return false;
 
   if (!PrerenderManager::IsPrerenderingPossible())
     return false;
 
   // Override any field trial groups if the user has set a command line flag.
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kPrerenderFromOmnibox)) {
     const std::string switch_value =
         CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
             switches::kPrerenderFromOmnibox);
 
     if (switch_value == switches::kPrerenderFromOmniboxSwitchValueEnabled)
       return true;
 
     if (switch_value == switches::kPrerenderFromOmniboxSwitchValueDisabled)
       return false;
 
     DCHECK(switch_value == switches::kPrerenderFromOmniboxSwitchValueAuto);
   }
 
   if (!MetricsServiceHelper::IsMetricsReportingEnabled())
     return false;
 
-  const int group = base::FieldTrialList::FindValue("PrerenderFromOmnibox");
+  const int group =
+      base::FieldTrialList::FindValue(kPrerenderFromOmniboxTrialName);
   return group != base::FieldTrial::kNotFinalized &&
          group != base::FieldTrial::kDefaultGroupNumber;
 }
 
 OmniboxHeuristic GetOmniboxHeuristicToUse() {
   const int group =
-      base::FieldTrialList::FindValue("PrerenderFromOmniboxHeuristic");
+      base::FieldTrialList::FindValue(kPrerenderFromOmniboxHeuristicTrialName);
   if (group == omnibox_original_group_id)
     return OMNIBOX_HEURISTIC_ORIGINAL;
   if (group == omnibox_conservative_group_id)
     return OMNIBOX_HEURISTIC_CONSERVATIVE;
   if (group == omnibox_exact_group_id)
     return OMNIBOX_HEURISTIC_EXACT;
+  if (group == omnibox_exact_full_group_id)
+    return OMNIBOX_HEURISTIC_EXACT_FULL;
 
   // If we don't have a group just return the original heuristic.
   return OMNIBOX_HEURISTIC_ORIGINAL;
 }
 
 std::string GetOmniboxHistogramSuffix() {
   return NameFromOmniboxHeuristic(prerender::GetOmniboxHeuristicToUse());
 }
 
 }  // namespace prerender