Clear client id prefs when opting out of UMA.

chrome/installer/util/google_update_settings.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 "chrome/installer/util/google_update_settings.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 311 matching lines @@
       root_key, reg_path.c_str(), KEY_SET_VALUE | KEY_WOW64_32KEY);
   if (result != ERROR_SUCCESS) {
     LOG(ERROR) << "Failed opening key " << reg_path << " to set "
                << google_update::kRegUsageStatsField << "; result: " << result;
   } else {
     result = key.WriteValue(google_update::kRegUsageStatsField, value);
     LOG_IF(ERROR, result != ERROR_SUCCESS) << "Failed setting "
         << google_update::kRegUsageStatsField << " in key " << reg_path
         << "; result: " << result;
   }
+
+  // When opting out, clear registry backup of client id and related values.
+  if (result == ERROR_SUCCESS && !consented)
+    GoogleUpdateSettings::StoreMetricsClientInfo(metrics::ClientInfo());

[grt (UTC plus 2), 2016/08/12 19:43:32]

nit: omit "GoogleUpdateSettings::"

[Alexei Svitkine (slow), 2016/08/12 22:29:58]

Done.

+
   return (result == ERROR_SUCCESS);
 }
 
 // static
 bool GoogleUpdateSettings::GetCollectStatsConsentDefault(
     bool* stats_consent_default) {
   BrowserDistribution* dist = BrowserDistribution::GetDistribution();
   installer::ChannelInfo channel_info;
   bool is_multi_install = false;
   if (InitChannelInfo(IsSystemInstall(), dist, &channel_info,
@@ skipping 687 matching lines @@
   }
 
   // If the key or value was not present, return the empty string.
   if (result == ERROR_FILE_NOT_FOUND || result == ERROR_PATH_NOT_FOUND) {
     experiment_labels->clear();
     return true;
   }
 
   return result == ERROR_SUCCESS;
 }