Multi-strategy based tracking.

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index 1410784c20f1e06698a06d1099827a64b0b0b4df..706b5d6d607ac5b3e344b7f4b8e6668bf7fce441 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -23,6 +23,7 @@
 #include "chrome/browser/prefs/pref_model_associator.h"
 #include "chrome/browser/prefs/pref_service_syncable.h"
 #include "chrome/browser/prefs/pref_service_syncable_factory.h"
+#include "chrome/browser/prefs/tracked_preference.h"
 #include "chrome/browser/ui/profile_error_dialog.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_prefs/pref_registry_syncable.h"
@@ -50,23 +51,65 @@ namespace {
 // tools/metrics/histograms/histograms.xml. To add a new preference, append it
 // to the array and add a corresponding value to the histogram enum. Each
 // tracked preference must be given a unique reporting ID.
-const PrefHashFilter::TrackedPreference kTrackedPrefs[] = {
-  { 0, prefs::kShowHomeButton, true },
-  { 1, prefs::kHomePageIsNewTabPage, true },
-  { 2, prefs::kHomePage, true },
-  { 3, prefs::kRestoreOnStartup, true },
-  { 4, prefs::kURLsToRestoreOnStartup, true },
-  { 5, prefs::kExtensionsPref, false },
-  { 6, prefs::kGoogleServicesLastUsername, true },
-  { 7, prefs::kSearchProviderOverrides, true },
-  { 8, prefs::kDefaultSearchProviderSearchURL, true },
-  { 9, prefs::kDefaultSearchProviderKeyword, true },
-  { 10, prefs::kDefaultSearchProviderName, true },
+const PrefHashFilter::TrackedPreferenceMetaData kTrackedPrefs[] = {
+  {
+    0, prefs::kShowHomeButton, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    1, prefs::kHomePageIsNewTabPage, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    2, prefs::kHomePage, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    3, prefs::kRestoreOnStartup, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    4, prefs::kURLsToRestoreOnStartup, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    5, prefs::kExtensionsPref, false,
+    PrefHashFilter::TRACKING_STRATEGY_SPLIT
+  },
+  {
+    6, prefs::kGoogleServicesLastUsername, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    7, prefs::kSearchProviderOverrides, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    8, prefs::kDefaultSearchProviderSearchURL, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    9, prefs::kDefaultSearchProviderKeyword, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    10, prefs::kDefaultSearchProviderName, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
 #if !defined(OS_ANDROID)
-  { 11, prefs::kPinnedTabs, true },
+  {
+    11, prefs::kPinnedTabs, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
 #endif
-  { 12, prefs::kExtensionKnownDisabled, true },
-  { 13, prefs::kProfileResetPromptMemento, true },
+  {
+    12, prefs::kExtensionKnownDisabled, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
+  {
+    13, prefs::kProfileResetPromptMemento, true,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
 };
 
 // The count of tracked preferences IDs across all platforms.
@@ -74,29 +117,33 @@ const size_t kTrackedPrefsReportingIDsCount = 14;
 COMPILE_ASSERT(kTrackedPrefsReportingIDsCount >= arraysize(kTrackedPrefs),
                need_to_increment_ids_count);
 
-PrefHashFilter::EnforcementLevel GetSettingsEnforcementLevel() {
+TrackedPreference::EnforcementLevel GetSettingsEnforcementLevel() {
   static const char kSettingsEnforcementExperiment[] = "SettingsEnforcement";
   struct {
     const char* level_name;
-    PrefHashFilter::EnforcementLevel level;
+    TrackedPreference::EnforcementLevel level;
   } static const kEnforcementLevelMap[] = {
     {
       "no_enforcement",
-      PrefHashFilter::NO_ENFORCEMENT
+      TrackedPreference::NO_ENFORCEMENT
     },
     {
       "enforce",
-      PrefHashFilter::ENFORCE
+      TrackedPreference::ENFORCE
     },
     {
       "enforce_no_seeding",
-      PrefHashFilter::ENFORCE_NO_SEEDING
+      TrackedPreference::ENFORCE_NO_SEEDING
     },
     {
       "enforce_no_seeding_no_migration",
-      PrefHashFilter::ENFORCE_NO_SEEDING_NO_MIGRATION
+      TrackedPreference::ENFORCE_NO_SEEDING_NO_MIGRATION
     },
   };
+  COMPILE_ASSERT(ARRAYSIZE_UNSAFE(kEnforcementLevelMap) ==
+                     (TrackedPreference::ENFORCE_ALL -
+                      TrackedPreference::NO_ENFORCEMENT),
+                 missing_enforcement_level);
 
   base::FieldTrial* trial =
       base::FieldTrialList::Find(kSettingsEnforcementExperiment);
@@ -112,7 +159,7 @@ PrefHashFilter::EnforcementLevel GetSettingsEnforcementLevel() {
     }
   }
   // TODO(gab): Switch default to ENFORCE_ALL when the field trial config is up.
-  return PrefHashFilter::NO_ENFORCEMENT;
+  return TrackedPreference::NO_ENFORCEMENT;
 }
 
 // Shows notifications which correspond to PersistentPrefStore's reading errors.