Turn Popular sites on by default.

components/ntp_tiles/field_trial.cc

Index: components/ntp_tiles/field_trial.cc
diff --git a/components/ntp_tiles/field_trial.cc b/components/ntp_tiles/field_trial.cc
index ce421dcc668e98387626bc629ea0e81a607a7b28..2513430162ea9c690bc0d856aaf6e1710e803679 100644
--- a/components/ntp_tiles/field_trial.cc
+++ b/components/ntp_tiles/field_trial.cc
@@ -43,17 +43,19 @@ void SetUpFirstLaunchFieldTrial(bool is_stable_channel) {
   if (base::FieldTrialList::TrialExists(kPopularSitesFieldTrialName))
     return;
 
+  // The experiment is only for stable.

[sfiera, 2017/02/03 14:02:34]

I wouldn't describe this as an experiment anymore with 90% enabled. It looks
like you're keeping around a holdback so that you can continue to get metrics.
I'd describe it that way.

[noyau (Ping after 24h), 2017/02/21 12:24:16]

It's an experiment to keep 10% disabled :)

+  if (!is_stable_channel)

[rkaplow, 2017/02/07 03:56:46]

maybe also comment on intended behavior of other channels

[noyau (Ping after 24h), 2017/02/21 12:24:16]

Done.

+    return;
+
   // Stable channels will run with 10% probability.
-  // Non-stable channels will run with 50% probability.
   const base::FieldTrial::Probability kTotalProbability = 100;
-  const base::FieldTrial::Probability kEnabledAndControlProbability =
-      is_stable_channel ? 10 : 50;
+  const base::FieldTrial::Probability kEnabledAndControlProbability = 10;
 
-  // Experiment enabled until March 15, 2017. By default, disabled.
+  // Experiment enabled until April 26, 2017.
   scoped_refptr<base::FieldTrial> trial(
       base::FieldTrialList::FactoryGetFieldTrial(
           kPopularSitesFieldTrialName, kTotalProbability,
-          kPopularSiteDefaultGroup, 2017, 3, 15,  // Mar 15, 2017
+          kPopularSiteDefaultGroup, 2017, 4, 26,  // Apr 26, 2017
           base::FieldTrial::ONE_TIME_RANDOMIZED, nullptr));
 
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
@@ -96,7 +98,9 @@ bool ShouldShowPopularSites() {
   }
 #endif
 
-  return base::StartsWith(group_name, "Enabled",
+  // The experiment is enabled by default.

[sfiera, 2017/02/03 14:02:34]

This should be restricted to iOS.

[noyau (Ping after 24h), 2017/02/21 12:24:16]

Done.

But is this really true? Does that mean that Android is off by default? I
thought the feature was always turned on for Android?

[sfiera, 2017/02/21 13:10:21]

Nope. We still don't have launch approval for all countries.

+  return group_name.empty() || (group_name == kPopularSiteDefaultGroup) ||
+         base::StartsWith(group_name, "Enabled",
                           base::CompareCase::INSENSITIVE_ASCII);
 }