Make it so disabled field trials are not reported as active.

base/metrics/field_trial.cc

 // Copyright (c) 2012 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 "base/metrics/field_trial.h"
 
 #include "base/build_time.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/rand_util.h"
@@ skipping 127 matching lines @@
   if (group_ == kNotFinalized && accumulated_group_probability_ > random_) {
     // This is the group that crossed the random line, so we do the assignment.
     SetGroupChoice(name, next_group_number_);
   }
   return next_group_number_++;
 }
 
 int FieldTrial::group() {
   FinalizeGroupChoice();
   if (!group_reported_) {
-    FieldTrialList::NotifyFieldTrialGroupSelection(name_, group_name_);
+    if (enable_field_trial_)

[Ilya Sherman, 2012/11/09 22:45:59]

optional nit: Maybe combine this with the if-stmt above?

[Alexei Svitkine (slow), 2012/11/09 23:42:39]

I thought of that, but then |group_reported_| wouldn't accurately track whether
group() was called externally (which wouldn't matter for the current use of that
variable, but may be useful to know in the future).

+      FieldTrialList::NotifyFieldTrialGroupSelection(name_, group_name_);
     group_reported_ = true;
   }
   return group_;
 }
 
 std::string FieldTrial::group_name() {
   // Call |group()| to ensure group gets assigned and observers are notified.
   group();
   DCHECK(!group_name_.empty());
   return group_name_;
@@ skipping 43 matching lines @@
   if (group_ != kNotFinalized)
     return;
   accumulated_group_probability_ = divisor_;
   // Here it's OK to use |kDefaultGroupNumber| since we can't be forced and not
   // finalized.
   DCHECK(!forced_);
   SetGroupChoice(default_group_name_, kDefaultGroupNumber);
 }
 
 bool FieldTrial::GetActiveGroup(ActiveGroup* active_group) const {
-  if (!group_reported_)
+  if (!group_reported_ || !enable_field_trial_)
     return false;
   DCHECK_NE(group_, kNotFinalized);
   active_group->trial = name_;
   active_group->group = group_name_;
   return true;
 }
 
 //------------------------------------------------------------------------------
 // FieldTrialList methods and members.
 
@@ skipping 237 matching lines @@
     used_without_global_ = true;
     return;
   }
   AutoLock auto_lock(global_->lock_);
   DCHECK(!global_->PreLockedFind(trial->name()));
   trial->AddRef();
   global_->registered_[trial->name()] = trial;
 }
 
 }  // namespace base