Revert 221944 "Add UMA to report Preferences File Corruption"

trunk/src/chrome/browser/prefs/pref_metrics_service.cc

Index: trunk/src/chrome/browser/prefs/pref_metrics_service.cc
===================================================================
--- trunk/src/chrome/browser/prefs/pref_metrics_service.cc	(revision 221965)
+++ trunk/src/chrome/browser/prefs/pref_metrics_service.cc	(working copy)
@@ -5,119 +5,48 @@
 #include "chrome/browser/prefs/pref_metrics_service.h"
 
 #include "base/bind.h"
-#include "base/command_line.h"
-#include "base/json/json_string_value_serializer.h"
 #include "base/metrics/histogram.h"
-#include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
-#include "base/strings/string_number_conversions.h"
-#include "chrome/browser/browser_process.h"
-#include "chrome/browser/browser_shutdown.h"
-// Accessing the Device ID API here is a layering violation.
-// TODO(bbudge) Move the API so it's usable here.
-// http://crbug.com/276485
-#include "chrome/browser/extensions/api/music_manager_private/device_id.h"
-#include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/prefs/pref_service_syncable.h"
-#include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/prefs/synced_pref_change_registrar.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/template_url_prepopulate_data.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
-#include "crypto/hmac.h"
-#include "grit/browser_resources.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
-#include "ui/base/resource/resource_bundle.h"
 
 namespace {
 
+// Converts a host name into a domain name for easier matching.
+std::string GetDomainFromHost(const std::string& host) {
+  return net::registry_controlled_domains::GetDomainAndRegistry(
+      host,
+      net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES);
+}
+
 const int kSessionStartupPrefValueMax = SessionStartupPref::kPrefValueMax;
 
-// These preferences must be kept in sync with the TrackedPreference enum in
-// tools/metrics/histograms/histograms.xml. To add a new preference, append it
-// to the array and add a corresponding value to the histogram enum.
-const char* kTrackedPrefs[] = {
-  prefs::kShowHomeButton,
-  prefs::kHomePageIsNewTabPage,
-  prefs::kHomePage,
-  prefs::kRestoreOnStartup,
-  prefs::kURLsToRestoreOnStartup,
-  prefs::kExtensionsPref,
-  prefs::kGoogleServicesLastUsername,
-  prefs::kSearchProviderOverrides,
-  prefs::kDefaultSearchProviderSearchURL,
-  prefs::kDefaultSearchProviderKeyword,
-  prefs::kDefaultSearchProviderName,
-#if !defined(OS_ANDROID)
-  prefs::kPinnedTabs,
-#endif
-};
-
-static const size_t kSHA256DigestSize = 32;
-
 }  // namespace
 
 PrefMetricsService::PrefMetricsService(Profile* profile)
-    : profile_(profile),
-      prefs_(profile_->GetPrefs()),
-      local_state_(g_browser_process->local_state()),
-      profile_name_(profile_->GetPath().AsUTF8Unsafe()),
-      tracked_pref_paths_(kTrackedPrefs),
-      tracked_pref_path_count_(arraysize(kTrackedPrefs)),
-      checked_tracked_prefs_(false),
-      weak_factory_(this) {
-  pref_hash_seed_ = ResourceBundle::GetSharedInstance().GetRawDataResource(
-      IDR_PREF_HASH_SEED_BIN).as_string();
-
+    : profile_(profile) {
   RecordLaunchPrefs();
 
   PrefServiceSyncable* prefs = PrefServiceSyncable::FromProfile(profile_);
   synced_pref_change_registrar_.reset(new SyncedPrefChangeRegistrar(prefs));
 
   RegisterSyncedPrefObservers();
-
-  // The following code might cause callbacks into this instance before we exit
-  // the constructor. This instance should be initialized at this point.
-
-  // Android has no GetDeviceId.
-#if !defined(OS_ANDROID)
-  // We need the machine id to compute pref value hashes. Fetch that, and then
-  // call CheckTrackedPreferences in the callback.
-  extensions::api::DeviceId::GetDeviceId(
-      "PrefMetricsService",  // non-empty string to obfuscate the device id.
-      Bind(&PrefMetricsService::GetDeviceIdCallback,
-           weak_factory_.GetWeakPtr()));
-#endif  // !defined(OS_ANDROID)
 }
 
-// For unit testing only.
-PrefMetricsService::PrefMetricsService(Profile* profile,
-                                       PrefService* local_state,
-                                       const std::string& device_id,
-                                       const char** tracked_pref_paths,
-                                       int tracked_pref_path_count)
-    : profile_(profile),
-      prefs_(profile->GetPrefs()),
-      local_state_(local_state),
-      pref_hash_seed_(kSHA256DigestSize, 0),
-      device_id_(device_id),
-      tracked_pref_paths_(tracked_pref_paths),
-      tracked_pref_path_count_(tracked_pref_path_count),
-      checked_tracked_prefs_(false),
-      weak_factory_(this) {
-  CheckTrackedPreferences();
-}
-
 PrefMetricsService::~PrefMetricsService() {
 }
 
 void PrefMetricsService::RecordLaunchPrefs() {
-  bool show_home_button = prefs_->GetBoolean(prefs::kShowHomeButton);
-  bool home_page_is_ntp = prefs_->GetBoolean(prefs::kHomePageIsNewTabPage);
+  PrefService* prefs = profile_->GetPrefs();
+  bool show_home_button = prefs->GetBoolean(prefs::kShowHomeButton);
+  bool home_page_is_ntp = prefs->GetBoolean(prefs::kHomePageIsNewTabPage);
   UMA_HISTOGRAM_BOOLEAN("Settings.ShowHomeButton", show_home_button);
   if (show_home_button) {
     UMA_HISTOGRAM_BOOLEAN("Settings.GivenShowHomeButton_HomePageIsNewTabPage",
@@ -131,7 +60,7 @@
   // (pages that share a TLD+1 with a known engine but aren't actually search
   // pages, e.g. plus.google.com).
   if (!home_page_is_ntp) {
-    GURL homepage_url(prefs_->GetString(prefs::kHomePage));
+    GURL homepage_url(prefs->GetString(prefs::kHomePage));
     if (homepage_url.is_valid()) {
       UMA_HISTOGRAM_ENUMERATION(
           "Settings.HomePageEngineType",
@@ -140,11 +69,11 @@
     }
   }
 
-  int restore_on_startup = prefs_->GetInteger(prefs::kRestoreOnStartup);
+  int restore_on_startup = prefs->GetInteger(prefs::kRestoreOnStartup);
   UMA_HISTOGRAM_ENUMERATION("Settings.StartupPageLoadSettings",
                             restore_on_startup, kSessionStartupPrefValueMax);
   if (restore_on_startup == SessionStartupPref::kPrefValueURLs) {
-    const ListValue* url_list = prefs_->GetList(prefs::kURLsToRestoreOnStartup);
+    const ListValue* url_list = prefs->GetList(prefs::kURLsToRestoreOnStartup);
     UMA_HISTOGRAM_CUSTOM_COUNTS("Settings.StartupPageLoadURLs",
                                 url_list->GetSize(), 1, 50, 20);
     // Similarly, check startup pages for known search engine TLD+1s.
@@ -163,13 +92,6 @@
   }
 }
 
-// static
-void PrefMetricsService::RegisterPrefs(PrefRegistrySimple* registry) {
-  // Register the top level dictionary to map profile names to dictionaries of
-  // tracked preferences.
-  registry->RegisterDictionaryPref(prefs::kProfilePreferenceHashes);
-}
-
 void PrefMetricsService::RegisterSyncedPrefObservers() {
   LogHistogramValueCallback booleanHandler = base::Bind(
       &PrefMetricsService::LogBooleanPrefChange, base::Unretained(this));
@@ -247,140 +169,6 @@
   }
 }
 
-void PrefMetricsService::GetDeviceIdCallback(const std::string& device_id) {
-  device_id_ = device_id;
-  // On Aura, this seems to be called twice.
-  if (!checked_tracked_prefs_)
-    CheckTrackedPreferences();
-}
-
-// To detect changes to Preferences that happen outside of Chrome, we hash
-// selected pref values and save them in local state. CheckTrackedPreferences
-// compares the saved values to the values observed in the profile's prefs. A
-// dictionary of dictionaries in local state holds the hashed values, grouped by
-// profile. To make the system more resistant to spoofing, pref values are
-// hashed with the pref path and the device id.
-void PrefMetricsService::CheckTrackedPreferences() {
-  DCHECK(!checked_tracked_prefs_);
-
-  const base::DictionaryValue* pref_hash_dicts =
-      local_state_->GetDictionary(prefs::kProfilePreferenceHashes);
-  // Get the hashed prefs dictionary if it exists. If it doesn't, it will be
-  // created if we set preference values below.
-  const base::DictionaryValue* hashed_prefs = NULL;
-  pref_hash_dicts->GetDictionary(profile_name_, &hashed_prefs);
-  for (int i = 0; i < tracked_pref_path_count_; ++i) {
-    // Skip prefs that haven't been registered.
-    if (!prefs_->FindPreference(tracked_pref_paths_[i]))
-      continue;
-
-    bool changed = false;
-    const base::Value* value = prefs_->GetUserPrefValue(tracked_pref_paths_[i]);
-    if (value) {
-      std::string value_hash =
-          GetHashedPrefValue(tracked_pref_paths_[i], value);
-      std::string last_hash;
-      if (hashed_prefs &&
-          hashed_prefs->GetString(tracked_pref_paths_[i], &last_hash)) {
-        if (value_hash != last_hash) {
-          changed = true;
-          // Record that the preference changed from its last value.
-          UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceChanged",
-              i, tracked_pref_path_count_);
-          UpdateTrackedPreference(tracked_pref_paths_[i]);
-        }
-      } else {
-        changed = true;
-        // Record that we haven't tracked this preference yet, or the hash in
-        // local state was removed.
-        UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceInitialized",
-            i, tracked_pref_path_count_);
-        UpdateTrackedPreference(tracked_pref_paths_[i]);
-      }
-    } else {
-      // There is no preference set. Remove any hashed value from local state
-      // and if one was present, record that a pref was cleared.
-      if (RemoveTrackedPreference(tracked_pref_paths_[i])) {
-        changed = true;
-        UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceCleared",
-            i, tracked_pref_path_count_);
-      }
-    }
-    if (!changed) {
-      UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceUnchanged",
-          i, tracked_pref_path_count_);
-    }
-  }
-
-  checked_tracked_prefs_ = true;
-
-  // Now that we've checked the incoming preferences, register for change
-  // notifications, unless this is test code.
-  // TODO(bbudge) Fix failing browser_tests so we can remove this test. Several
-  // tests fail when they shutdown before they can write local state.
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kTestType))
-    InitializePrefObservers();
-}
-
-void PrefMetricsService::UpdateTrackedPreference(const char* path) {
-  const base::Value* value = prefs_->GetUserPrefValue(path);
-  if (value) {
-    DictionaryPrefUpdate update(local_state_, prefs::kProfilePreferenceHashes);
-    update->SetString(GetHashedPrefPath(path),
-                      GetHashedPrefValue(path, value));
-  } else {
-    RemoveTrackedPreference(path);
-  }
-}
-
-bool PrefMetricsService::RemoveTrackedPreference(const char* path) {
-  DictionaryPrefUpdate update(local_state_, prefs::kProfilePreferenceHashes);
-  return update->Remove(GetHashedPrefPath(path), NULL);
-}
-
-std::string PrefMetricsService::GetHashedPrefPath(const char* path) {
-  std::string hash_pref_path(profile_name_);
-  hash_pref_path.append(".");
-  hash_pref_path.append(path);
-  return hash_pref_path;
-}
-
-std::string PrefMetricsService::GetHashedPrefValue(
-    const char* path,
-    const base::Value* value) {
-  DCHECK(value);
-
-  std::string string_to_hash(device_id_);
-  string_to_hash.append(path);
-  JSONStringValueSerializer serializer(&string_to_hash);
-  serializer.Serialize(*value);
-
-  crypto::HMAC hmac(crypto::HMAC::SHA256);
-  unsigned char digest[kSHA256DigestSize];
-  if (!hmac.Init(pref_hash_seed_) ||
-      !hmac.Sign(string_to_hash, digest, kSHA256DigestSize)) {
-    NOTREACHED();
-    return std::string();
-  }
-
-  return base::HexEncode(digest, kSHA256DigestSize);
-}
-
-void PrefMetricsService::InitializePrefObservers() {
-  pref_registrar_.Init(prefs_);
-  for (int i = 0; i < tracked_pref_path_count_; ++i) {
-    // Skip prefs that haven't been registered.
-    if (!prefs_->FindPreference(tracked_pref_paths_[i]))
-      continue;
-
-    pref_registrar_.Add(
-        tracked_pref_paths_[i],
-        base::Bind(&PrefMetricsService::UpdateTrackedPreference,
-                   weak_factory_.GetWeakPtr(),
-                   tracked_pref_paths_[i]));
-  }
-}
-
 // static
 PrefMetricsService::Factory* PrefMetricsService::Factory::GetInstance() {
   return Singleton<PrefMetricsService::Factory>::get();