Supporting study definitions without default groups and end_date filtering.

components/variations/processed_study.cc

 // Copyright 2013 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 "components/variations/processed_study.h"
 
 #include <set>
 #include <string>
 
 #include "base/version.h"
 #include "components/variations/proto/study.pb.h"
 
 namespace variations {
 
 namespace {
 
 // Validates the sanity of |study| and computes the total probability and
 // whether all assignments are to a single group.
 bool ValidateStudyAndComputeTotalProbability(
     const Study& study,
     base::FieldTrial::Probability* total_probability,
     bool* all_assignments_to_one_group,
     std::string* single_feature_name) {
-  // At the moment, a missing default_experiment_name makes the study invalid.
-  if (study.default_experiment_name().empty()) {
-    DVLOG(1) << study.name() << " has no default experiment defined.";
-    return false;
-  }
   if (study.filter().has_min_version() &&
       !base::Version::IsValidWildcardString(study.filter().min_version())) {
     DVLOG(1) << study.name() << " has invalid min version: "
              << study.filter().min_version();
     return false;
   }
   if (study.filter().has_max_version() &&
       !base::Version::IsValidWildcardString(study.filter().max_version())) {
     DVLOG(1) << study.name() << " has invalid max version: "
              << study.filter().max_version();
@@ skipping 46 matching lines @@
     if (!experiment.has_forcing_flag() && experiment.probability_weight() > 0) {
       // If |divisor| is not 0, there was at least one prior non-zero group.
       if (divisor != 0)
         multiple_assigned_groups = true;
       divisor += experiment.probability_weight();
     }
     if (study.experiment(i).name() == default_group_name)
       found_default_group = true;
   }
 
-  if (!found_default_group) {
+  // Specifying a default experiment is optional, so finding it in the
+  // experiment list is only required when it is specified.
+  if (!study.default_experiment_name().empty() && !found_default_group) {
     DVLOG(1) << study.name() << " is missing default experiment in its "

[rkaplow, 2017/01/04 15:58:25]

optional, could add default_group_name to the DVLOG

[jwd, 2017/01/04 21:10:22]

Done.

              << "experiment list";
     // The default group was not found in the list of groups. This study is not
     // valid.
     return false;
   }
 
   if (!has_multiple_features && !single_feature_name_seen.empty())
     single_feature_name->swap(single_feature_name_seen);
   else
     single_feature_name->clear();
 
   *total_probability = divisor;
   *all_assignments_to_one_group = !multiple_assigned_groups;
   return true;
 }
 
 
 }  // namespace
 
+// static
+const std::string ProcessedStudy::kGenericDefaultExperimentName =
+    "VariationsDefaultExperiment";
+
 ProcessedStudy::ProcessedStudy()
     : study_(NULL),
       total_probability_(0),
       all_assignments_to_one_group_(false),
       is_expired_(false) {
 }
 
 ProcessedStudy::~ProcessedStudy() {
 }
 
@@ skipping 17 matching lines @@
 
 int ProcessedStudy::GetExperimentIndexByName(const std::string& name) const {
   for (int i = 0; i < study_->experiment_size(); ++i) {
     if (study_->experiment(i).name() == name)
       return i;
   }
 
   return -1;
 }
 
+const std::string& ProcessedStudy::GetDefaultExperimentName() const {
+  if (study_->default_experiment_name().empty())
+    return kGenericDefaultExperimentName;
+
+  return study_->default_experiment_name();
+}
+
 // static
 bool ProcessedStudy::ValidateAndAppendStudy(
     const Study* study,
     bool is_expired,
     std::vector<ProcessedStudy>* processed_studies) {
   ProcessedStudy processed_study;
   if (processed_study.Init(study, is_expired)) {
     processed_studies->push_back(processed_study);
     return true;
   }
   return false;
 }
 
 }  // namespace variations