Add back a check for improper usage of IsOneTimeRandomizationEnabled.

base/metrics/field_trial.cc

Index: base/metrics/field_trial.cc
diff --git a/base/metrics/field_trial.cc b/base/metrics/field_trial.cc
index 190ebcf0254a2bb0021464e8659100d423585106..2c87f073492e66cbb01d8303abb34155945b766e 100644
--- a/base/metrics/field_trial.cc
+++ b/base/metrics/field_trial.cc
@@ -189,14 +189,14 @@ double FieldTrial::HashClientId(const std::string& client_id,
 FieldTrialList* FieldTrialList::global_ = NULL;
 
 // static
-bool FieldTrialList::register_without_global_ = false;
+bool FieldTrialList::used_without_global_ = false;
 
 FieldTrialList::FieldTrialList(const std::string& client_id)
     : application_start_time_(TimeTicks::Now()),
       client_id_(client_id),
       observer_list_(ObserverList<Observer>::NOTIFY_EXISTING_ONLY) {
   DCHECK(!global_);
-  DCHECK(!register_without_global_);
+  DCHECK(!used_without_global_);
   global_ = this;
 
   Time::Exploded exploded;
@@ -220,7 +220,7 @@ FieldTrialList::~FieldTrialList() {
 // static
 void FieldTrialList::Register(FieldTrial* trial) {
   if (!global_) {
-    register_without_global_ = true;
+    used_without_global_ = true;
     return;
   }
   AutoLock auto_lock(global_->lock_);
@@ -369,11 +369,10 @@ size_t FieldTrialList::GetFieldTrialCount() {
 
 // static
 bool FieldTrialList::IsOneTimeRandomizationEnabled() {
-  // TODO(joi): Put back a DCHECK(global_) here.  First, need to make sure all
-  // unit test executables have exactly one FieldTrialList instance (currently
-  // they have 0 or 1).
-  if (!global_)
+  if (!global_) {
+    used_without_global_ = true;
     return false;
+  }
 
   return !global_->client_id_.empty();
 }