Add field trial to extend prerender expiration to 5 minutes.

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 e5174b6eaa804326158fe81667d97362dae5c220..b9998271c78419086e99354fd302132338f00d9f 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -42,31 +42,42 @@ void SetupPrefetchFieldTrial() {
 }
 
 void SetupPrerenderFieldTrial() {
-  base::FieldTrial::Probability divisor = 1000;
+  base::FieldTrial::Probability divisor = 1200;
+
   base::FieldTrial::Probability exp1_probability = 200;
+  base::FieldTrial::Probability exp1_long_ttl_probability = 100;

[cbentzel, 2012/02/28 00:53:41]

Should this be named "5 minute TTL" or something explicit like that? If we
wanted to do another experiment with 10 minutes don't want to name it "longer"
or reuse "long" . 

[dominich, 2012/02/28 17:51:31]

Done.

   base::FieldTrial::Probability control1_probability = 200;
   base::FieldTrial::Probability no_use1_probability = 100;
+
   base::FieldTrial::Probability exp2_probability = 200;
+  base::FieldTrial::Probability exp2_long_ttl_probability = 100;
   base::FieldTrial::Probability control2_probability = 200;
   base::FieldTrial::Probability no_use2_probability = 100;
+
   chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
   if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
       channel == chrome::VersionInfo::CHANNEL_BETA) {
-    exp1_probability = 495;
-    control1_probability = 5;
+    exp1_probability = 588;
+    exp1_long_ttl_probability = 6;
+    control1_probability = 6;
     no_use1_probability = 0;
-    exp2_probability = 495;
-    control2_probability = 5;
+    exp2_probability = 588;
+    exp2_long_ttl_probability = 6;
+    control2_probability = 6;
     no_use2_probability = 0;
   }
-  CHECK_EQ(divisor, exp1_probability + control1_probability +
-           no_use1_probability + exp2_probability +
-           control2_probability + no_use2_probability);
+  CHECK_EQ(divisor, exp1_probability + exp1_long_ttl_probability +
+           control1_probability + no_use1_probability + exp2_probability +
+           exp2_long_ttl_probability + control2_probability +
+           no_use2_probability);
   scoped_refptr<base::FieldTrial> trial(
       new base::FieldTrial("Prerender", divisor,
                            "ContentPrefetchPrerender1", 2012, 6, 30));
 
   const int kExperiment1Group = trial->kDefaultGroupNumber;
+  const int kExperiment1LongTTLGroup =
+      trial->AppendGroup("ContentPrefetchPrerenderExpLongTTL1",
+                         exp1_long_ttl_probability);
   const int kControl1Group =
       trial->AppendGroup("ContentPrefetchPrerenderControl1",
                          control1_probability);
@@ -76,6 +87,9 @@ void SetupPrerenderFieldTrial() {
   const int kExperiment2Group =
       trial->AppendGroup("ContentPrefetchPrerender2",
                          exp2_probability);
+  const int kExperiment2LongTTLGroup =
+      trial->AppendGroup("ContentPrefetchPrerenderExpLongTTL2",
+                         exp2_long_ttl_probability);
   const int kControl2Group =
       trial->AppendGroup("ContentPrefetchPrerenderControl2",
                          control2_probability);
@@ -87,6 +101,10 @@ void SetupPrerenderFieldTrial() {
       trial_group == kExperiment2Group) {
     PrerenderManager::SetMode(
         PrerenderManager::PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP);
+  } else if (trial_group == kExperiment1LongTTLGroup ||
+             trial_group == kExperiment2LongTTLGroup) {
+    PrerenderManager::SetMode(
+        PrerenderManager::PRERENDER_MODE_EXPERIMENT_LONG_TTL_GROUP);
   } else if (trial_group == kControl1Group ||
              trial_group == kControl2Group) {
     PrerenderManager::SetMode(