Adding a fourth omnibox prerender experiment.

chrome/browser/prerender/prerender_field_trial.cc

Index: chrome/browser/prerender/prerender_field_trial.cc
diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index 4c3344e903eb30331286a4ab0ba83e99668211e9..01e5b5969f75c5453ee5e36605736d03836f3add 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -23,11 +23,13 @@ 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);
@@ -172,8 +174,9 @@ void ConfigurePrerenderFromOmnibox() {
   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,
                            "OriginalAlgorithm", 2012, 8, 30));
@@ -183,6 +186,8 @@ void ConfigurePrerenderFromOmnibox() {
                                    kConservativeProbability);
   omnibox_exact_group_id =
       heuristic_trial->AppendGroup("ExactAlgorithm", kExactProbability);
+  omnibox_exact_full_group_id =
+      heuristic_trial->AppendGroup("ExactFullAlgorithm", kExactFullProbability);
 }
 
 bool IsOmniboxEnabled(Profile* profile) {
@@ -225,6 +230,8 @@ OmniboxHeuristic GetOmniboxHeuristicToUse() {
     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;