Activate prepopulated fieldtrials

chrome/common/variations/variations_util.cc

Index: chrome/common/variations/variations_util.cc
diff --git a/chrome/common/variations/variations_util.cc b/chrome/common/variations/variations_util.cc
index 35b5bfd0d8053e5547fe4773808d6a738c6d913e..3487bc5d2813742030c2e73e7262f828b3653a19 100644
--- a/chrome/common/variations/variations_util.cc
+++ b/chrome/common/variations/variations_util.cc
@@ -7,9 +7,11 @@
 #include <string>
 #include <vector>
 
+#include "base/metrics/field_trial.h"
 #include "base/strings/string_split.h"
 #include "chrome/common/child_process_logging.h"
 #include "chrome/common/crash_keys.h"
+#include "chrome/common/variations/fieldtrial_testing_config.h"
 #include "components/variations/active_field_trials.h"
 #include "components/variations/variations_associated_data.h"
 #include "net/base/escape.h"
@@ -63,4 +65,22 @@ bool AssociateParamsFromString(const std::string& varations_string) {
   return true;
 }
 
+bool AssociateParamsFromFieldTrialConfig() {

[Alexei Svitkine (slow), 2015/07/08 17:10:17]

Can you add a test?

Maybe make a helper function that takes the struct as a param, so that it can be
tested with mock data. The test can then verify whether params and field trials
have been registered based on the contents of the struct.

[danduong, 2015/07/09 21:35:54]

Done.

+  for (size_t i = 0; i < kFieldTrialConfig.groups_size; ++i) {
+    const FieldTrialTestingGroup& group = kFieldTrialConfig.groups[i];
+    if (group.params_size) {

[Alexei Svitkine (slow), 2015/07/08 17:10:17]

Nit: Since this is a number, explicitly != 0 for clarity.

[danduong, 2015/07/09 21:35:54]

Done.

+      std::map<std::string, std::string> params;
+      for (size_t j = 0; j < group.params_size; ++j) {
+        const FieldTrialGroupParams& param = group.params[j];
+        params[EscapeValue(param.key)] = EscapeValue(param.value);
+      }
+      std::string trial = EscapeValue(group.study);
+      std::string group_name = EscapeValue(group.group_name);
+      variations::AssociateVariationParams(trial, group_name, params);
+    }
+    base::FieldTrialList::CreateFieldTrial(group.study, group.group_name);
+  }
+  return true;
+}
+
 }  // namespace chrome_variations