1 files changed, 40 insertions, 0 deletions
diff --git a/base/field_trial.cc b/base/field_trial.cc
index d0085e6..fc12f31 100644
--- a/base/field_trial.cc
+++ b/base/field_trial.cc
@@ -13,6 +13,9 @@ using base::Time;
 // static
 const int FieldTrial::kNotParticipating = -1;
 
+// static
+const char FieldTrial::kPersistentStringSeparator('/');
+
 //------------------------------------------------------------------------------
 // FieldTrial methods and members.
 
@@ -50,6 +53,40 @@ std::string FieldTrial::MakeName(const std::string& name_prefix,
   return big_string.append(FieldTrialList::FindFullName(trial_name));
 }
 
+std::string FieldTrial::MakePersistentString() const {
+  DCHECK_EQ(name_.find(kPersistentStringSeparator), std::string::npos);
+  DCHECK_EQ(group_name_.find(kPersistentStringSeparator), std::string::npos);
+
+  std::string persistent(name_);
+  persistent = persistent.append(1, kPersistentStringSeparator);
+  persistent = persistent.append(group_name_);
+  return persistent;
+}
+
+// static
+FieldTrial* FieldTrial::RestorePersistentString(const std::string &persistent) {
+  size_t split_point = persistent.find(kPersistentStringSeparator);
+  if (std::string::npos == split_point)
+    return NULL;  // Bogus string.
+  std::string new_name(persistent, 0, split_point);
+  std::string new_group_name(persistent, split_point + 1);
+  if (new_name.empty() || new_group_name.empty())
+    return NULL;  // Incomplete string.
+
+  FieldTrial *field_trial;
+  field_trial = FieldTrialList::Find(new_name);
+  if (field_trial) {
+    // In single process mode, we may have already created the field trial.
+    if (field_trial->group_name_ != new_group_name)
+      return NULL;  // Conflicting group name :-(.
+  } else {
+    const int kTotalProbability = 100;
+    field_trial = new FieldTrial(new_name, kTotalProbability);
+    field_trial->AppendGroup(new_group_name, kTotalProbability);
+  }
+  return field_trial;
+}
+
 //------------------------------------------------------------------------------
 // FieldTrialList methods and members.
 
@@ -75,6 +112,9 @@ FieldTrialList::~FieldTrialList() {
 
 // static
 void FieldTrialList::Register(FieldTrial* trial) {
+  DCHECK(global_);
+  if (!global_)
+    return;
   AutoLock auto_lock(global_->lock_);
   DCHECK(!global_->PreLockedFind(trial->name()));
   trial->AddRef();