Add more debugging CHECKS to diagnose an Android renderer crash.

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 b417b056d24f49946e3cda58c87b60b163dc26c3..866c53a10e979e6186099157c18804077bb7f744 100644
--- a/base/metrics/field_trial.cc
+++ b/base/metrics/field_trial.cc
@@ -638,7 +638,7 @@ void FieldTrialList::Register(FieldTrial* trial) {
     return;
   }
   AutoLock auto_lock(global_->lock_);
-  DCHECK(!global_->PreLockedFind(trial->trial_name()));
+  CHECK(!global_->PreLockedFind(trial->trial_name())) << trial->trial_name();
   trial->AddRef();
   trial->SetTrialRegistered();
   global_->registered_[trial->trial_name()] = trial;