Split the NullInitialized signal out of TrustedInitialized.

chrome/browser/prefs/tracked/tracked_preference_helper.cc

 // Copyright 2014 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 "chrome/browser/prefs/tracked/tracked_preference_helper.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 
 TrackedPreferenceHelper::TrackedPreferenceHelper(
     const std::string& pref_path,
     size_t reporting_id,
     size_t reporting_ids_count,
     PrefHashFilter::EnforcementLevel enforcement_level)
     : pref_path_(pref_path),
       reporting_id_(reporting_id), reporting_ids_count_(reporting_ids_count),
       enforce_(enforcement_level == PrefHashFilter::ENFORCE_ON_LOAD) {
 }
 
 TrackedPreferenceHelper::ResetAction TrackedPreferenceHelper::GetAction(
     PrefHashStoreTransaction::ValueState value_state) const {
   switch (value_state) {
     case PrefHashStoreTransaction::UNCHANGED:
       // Desired case, nothing to do.
       return DONT_RESET;
     case PrefHashStoreTransaction::CLEARED:
       // Unfortunate case, but there is nothing we can do.
       return DONT_RESET;
+    case PrefHashStoreTransaction::TRUSTED_NULL_VALUE:  // Falls through.
     case PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE:
       // It is okay to seed the hash in this case.
       return DONT_RESET;
     case PrefHashStoreTransaction::SECURE_LEGACY:
       // Accept secure legacy device ID based hashes.
       return DONT_RESET;
     case PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE:  // Falls through.
     case PrefHashStoreTransaction::CHANGED:
       return enforce_ ? DO_RESET : WANTED_RESET;
   }
@@ skipping 23 matching lines @@
                                 reporting_id_, reporting_ids_count_);
       return;
     case PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE:
       UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceInitialized",
                                 reporting_id_, reporting_ids_count_);
       return;
     case PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE:
       UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceTrustedInitialized",
                                 reporting_id_, reporting_ids_count_);
       return;
+    case PrefHashStoreTransaction::TRUSTED_NULL_VALUE:
+      UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceNullInitialized",
+                                reporting_id_, reporting_ids_count_);
+      return;
   }
   NOTREACHED() << "Unexpected PrefHashStoreTransaction::ValueState: "
                << value_state;
 }
 
 void TrackedPreferenceHelper::ReportAction(ResetAction reset_action) const {
   switch (reset_action) {
     case DONT_RESET:
       // No report for DONT_RESET.
       break;
@@ skipping 15 matching lines @@
   // Note: The factory creates and owns the histogram.
   base::HistogramBase* histogram =
       base::LinearHistogram::FactoryGet(
           "Settings.TrackedSplitPreferenceChanged." + pref_path_,
           1,
           100,  // Allow counts up to 100.
           101,
           base::HistogramBase::kUmaTargetedHistogramFlag);
   histogram->Add(count);
 }