Move MetricsStateManager into the Metrics component.

chrome/browser/metrics/metrics_state_manager.cc

Index: chrome/browser/metrics/metrics_state_manager.cc
diff --git a/chrome/browser/metrics/metrics_state_manager.cc b/chrome/browser/metrics/metrics_state_manager.cc
deleted file mode 100644
index e6024705f211367ceb4cfda2d07a722d21e47cad..0000000000000000000000000000000000000000
--- a/chrome/browser/metrics/metrics_state_manager.cc
+++ /dev/null
@@ -1,218 +0,0 @@
-// 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/metrics_state_manager.h"
-
-#include "base/command_line.h"
-#include "base/guid.h"
-#include "base/metrics/histogram.h"
-#include "base/metrics/sparse_histogram.h"
-#include "base/prefs/pref_registry_simple.h"
-#include "base/prefs/pref_service.h"
-#include "base/rand_util.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/time/time.h"
-#include "chrome/common/chrome_switches.h"
-#include "chrome/common/pref_names.h"
-#include "components/metrics/cloned_install_detector.h"
-#include "components/metrics/machine_id_provider.h"
-#include "components/metrics/metrics_pref_names.h"
-#include "components/variations/caching_permuted_entropy_provider.h"
-
-namespace metrics {
-
-namespace {
-
-// The argument used to generate a non-identifying entropy source. We want no
-// more than 13 bits of entropy, so use this max to return a number in the range
-// [0, 7999] as the entropy source (12.97 bits of entropy).
-const int kMaxLowEntropySize = 8000;
-
-// Default prefs value for ::prefs::kMetricsLowEntropySource to indicate that
-// the value has not yet been set.
-const int kLowEntropySourceNotSet = -1;
-
-// Generates a new non-identifying entropy source used to seed persistent
-// activities.
-int GenerateLowEntropySource() {
-  return base::RandInt(0, kMaxLowEntropySize - 1);
-}
-
-}  // namespace
-
-// static
-bool MetricsStateManager::instance_exists_ = false;
-
-MetricsStateManager::MetricsStateManager(
-    PrefService* local_state,
-    const base::Callback<bool(void)>& is_reporting_enabled_callback)
-    : local_state_(local_state),
-      is_reporting_enabled_callback_(is_reporting_enabled_callback),
-      low_entropy_source_(kLowEntropySourceNotSet),
-      entropy_source_returned_(ENTROPY_SOURCE_NONE) {
-  ResetMetricsIDsIfNecessary();
-  if (IsMetricsReportingEnabled())
-    ForceClientIdCreation();
-
-  DCHECK(!instance_exists_);
-  instance_exists_ = true;
-}
-
-MetricsStateManager::~MetricsStateManager() {
-  DCHECK(instance_exists_);
-  instance_exists_ = false;
-}
-
-bool MetricsStateManager::IsMetricsReportingEnabled() {
-  return is_reporting_enabled_callback_.Run();
-}
-
-void MetricsStateManager::ForceClientIdCreation() {
-  if (!client_id_.empty())
-    return;
-
-  client_id_ = local_state_->GetString(::prefs::kMetricsClientID);
-  if (!client_id_.empty())
-    return;
-
-  client_id_ = base::GenerateGUID();
-  local_state_->SetString(::prefs::kMetricsClientID, client_id_);
-
-  if (local_state_->GetString(::prefs::kMetricsOldClientID).empty()) {
-    // Record the timestamp of when the user opted in to UMA.
-    local_state_->SetInt64(::prefs::kMetricsReportingEnabledTimestamp,
-                           base::Time::Now().ToTimeT());
-  } else {
-    UMA_HISTOGRAM_BOOLEAN("UMA.ClientIdMigrated", true);
-  }
-  local_state_->ClearPref(::prefs::kMetricsOldClientID);
-}
-
-void MetricsStateManager::CheckForClonedInstall(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
-  DCHECK(!cloned_install_detector_);
-
-  MachineIdProvider* provider = MachineIdProvider::CreateInstance();
-  if (!provider)
-    return;
-
-  cloned_install_detector_.reset(new ClonedInstallDetector(provider));
-  cloned_install_detector_->CheckForClonedInstall(local_state_, task_runner);
-}
-
-scoped_ptr<const base::FieldTrial::EntropyProvider>
-MetricsStateManager::CreateEntropyProvider() {
-  // For metrics reporting-enabled users, we combine the client ID and low
-  // entropy source to get the final entropy source. Otherwise, only use the low
-  // entropy source.
-  // This has two useful properties:
-  //  1) It makes the entropy source less identifiable for parties that do not
-  //     know the low entropy source.
-  //  2) It makes the final entropy source resettable.
-  const int low_entropy_source_value = GetLowEntropySource();
-  UMA_HISTOGRAM_SPARSE_SLOWLY("UMA.LowEntropySourceValue",
-                              low_entropy_source_value);
-  if (IsMetricsReportingEnabled()) {
-    if (entropy_source_returned_ == ENTROPY_SOURCE_NONE)
-      entropy_source_returned_ = ENTROPY_SOURCE_HIGH;
-    DCHECK_EQ(ENTROPY_SOURCE_HIGH, entropy_source_returned_);
-    const std::string high_entropy_source =
-        client_id_ + base::IntToString(low_entropy_source_value);
-    return scoped_ptr<const base::FieldTrial::EntropyProvider>(
-        new SHA1EntropyProvider(high_entropy_source));
-  }
-
-  if (entropy_source_returned_ == ENTROPY_SOURCE_NONE)
-    entropy_source_returned_ = ENTROPY_SOURCE_LOW;
-  DCHECK_EQ(ENTROPY_SOURCE_LOW, entropy_source_returned_);
-
-#if defined(OS_ANDROID) || defined(OS_IOS)
-  return scoped_ptr<const base::FieldTrial::EntropyProvider>(
-      new CachingPermutedEntropyProvider(local_state_,
-                                         low_entropy_source_value,
-                                         kMaxLowEntropySize));
-#else
-  return scoped_ptr<const base::FieldTrial::EntropyProvider>(
-      new PermutedEntropyProvider(low_entropy_source_value,
-                                  kMaxLowEntropySize));
-#endif
-}
-
-// static
-scoped_ptr<MetricsStateManager> MetricsStateManager::Create(
-    PrefService* local_state,
-    const base::Callback<bool(void)>& is_reporting_enabled_callback) {
-  scoped_ptr<MetricsStateManager> result;
-  // Note: |instance_exists_| is updated in the constructor and destructor.
-  if (!instance_exists_) {
-    result.reset(
-        new MetricsStateManager(local_state, is_reporting_enabled_callback));
-  }
-  return result.Pass();
-}
-
-// static
-void MetricsStateManager::RegisterPrefs(PrefRegistrySimple* registry) {
-  registry->RegisterBooleanPref(prefs::kMetricsResetIds, false);
-  registry->RegisterStringPref(::prefs::kMetricsClientID, std::string());
-  registry->RegisterInt64Pref(::prefs::kMetricsReportingEnabledTimestamp, 0);
-  registry->RegisterIntegerPref(::prefs::kMetricsLowEntropySource,
-                                kLowEntropySourceNotSet);
-
-  ClonedInstallDetector::RegisterPrefs(registry);
-  CachingPermutedEntropyProvider::RegisterPrefs(registry);
-
-  // TODO(asvitkine): Remove these once a couple of releases have passed.
-  // http://crbug.com/357704
-  registry->RegisterStringPref(::prefs::kMetricsOldClientID, std::string());
-  registry->RegisterIntegerPref(::prefs::kMetricsOldLowEntropySource, 0);
-}
-
-int MetricsStateManager::GetLowEntropySource() {
-  // Note that the default value for the low entropy source and the default pref
-  // value are both kLowEntropySourceNotSet, which is used to identify if the
-  // value has been set or not.
-  if (low_entropy_source_ != kLowEntropySourceNotSet)
-    return low_entropy_source_;
-
-  const CommandLine* command_line(CommandLine::ForCurrentProcess());
-  // Only try to load the value from ::prefs if the user did not request a
-  // reset.
-  // Otherwise, skip to generating a new value.
-  if (!command_line->HasSwitch(switches::kResetVariationState)) {
-    int value = local_state_->GetInteger(::prefs::kMetricsLowEntropySource);
-    // If the value is outside the [0, kMaxLowEntropySize) range, re-generate
-    // it below.
-    if (value >= 0 && value < kMaxLowEntropySize) {
-      low_entropy_source_ = value;
-      UMA_HISTOGRAM_BOOLEAN("UMA.GeneratedLowEntropySource", false);
-      return low_entropy_source_;
-    }
-  }
-
-  UMA_HISTOGRAM_BOOLEAN("UMA.GeneratedLowEntropySource", true);
-  low_entropy_source_ = GenerateLowEntropySource();
-  local_state_->SetInteger(::prefs::kMetricsLowEntropySource,
-                           low_entropy_source_);
-  local_state_->ClearPref(::prefs::kMetricsOldLowEntropySource);
-  CachingPermutedEntropyProvider::ClearCache(local_state_);
-
-  return low_entropy_source_;
-}
-
-void MetricsStateManager::ResetMetricsIDsIfNecessary() {
-  if (!local_state_->GetBoolean(prefs::kMetricsResetIds))
-    return;
-
-  UMA_HISTOGRAM_BOOLEAN("UMA.MetricsIDsReset", true);
-
-  DCHECK(client_id_.empty());
-  DCHECK_EQ(kLowEntropySourceNotSet, low_entropy_source_);
-
-  local_state_->ClearPref(::prefs::kMetricsClientID);
-  local_state_->ClearPref(::prefs::kMetricsLowEntropySource);
-  local_state_->ClearPref(prefs::kMetricsResetIds);
-}
-
-}  // namespace metrics