Resetting metrics ids on clump detection.

chrome/browser/metrics/cloned_install_detector.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/metrics/cloned_install_detector.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
@@ skipping 31 matching lines @@
 
 }  // namespace
 
 ClonedInstallDetector::ClonedInstallDetector(MachineIdProvider* raw_id_provider)
     : raw_id_provider_(raw_id_provider),
       weak_ptr_factory_(this) {}
 
 ClonedInstallDetector::~ClonedInstallDetector() {}
 
 void ClonedInstallDetector::CheckForClonedInstall(PrefService* local_state) {
-  content::BrowserThread::PostTaskAndReplyWithResult(
+  DVLOG(2) << "\n\nabout to post some tasks.\n\n";
+  bool res = content::BrowserThread::PostTaskAndReplyWithResult(
       content::BrowserThread::FILE,
       FROM_HERE,
       base::Bind(&metrics::MachineIdProvider::GetMachineId,
                  raw_id_provider_),
       base::Bind(&metrics::ClonedInstallDetector::SaveMachineId,
                  weak_ptr_factory_.GetWeakPtr(),
                  local_state));
+  DVLOG(2) << "\n\ntask posted? " << res << "\n\n";
 }
 
 void ClonedInstallDetector::SaveMachineId(
     PrefService* local_state,
     std::string raw_id) {
+  DVLOG(2) << "\n\nsaving id: " << raw_id << "\n\n";
   if (raw_id.empty()) {
     LogMachineIdState(ID_GENERATION_FAILED);
     local_state->ClearPref(prefs::kMetricsMachineId);
     return;
   }
 
   int hashed_id = HashRawId(raw_id);
 
   MachineIdState id_state = ID_NO_STORED_VALUE;
   if (local_state->HasPrefPath(prefs::kMetricsMachineId)) {
-    id_state = local_state->GetInteger(prefs::kMetricsMachineId) == hashed_id ?
-        ID_UNCHANGED : ID_CHANGED;
+    if (local_state->GetInteger(prefs::kMetricsMachineId) != hashed_id) {
+      id_state = ID_CHANGED;
+      local_state->SetBoolean(prefs::kMetricsResetIds, true);

[Alexei Svitkine (slow), 2014/03/28 16:30:48]

Can this be a callback passed to this class at construction time? That way,
MetricsService can be the one to reset the pref.

(I'm okay with making this a TODO for this CL, though.)

[jwd, 2014/03/28 18:59:21]

Done.

+    } else {
+      id_state = ID_UNCHANGED;
+    }
   }
 
   LogMachineIdState(id_state);
 
   local_state->SetInteger(prefs::kMetricsMachineId, hashed_id);
 }
 
 // static
 void ClonedInstallDetector::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterIntegerPref(prefs::kMetricsMachineId, 0);
 }
 
 }  // namespace metrics