Organizing model type, notification type, root tag and model type string in map

so that all value at one place to avoid clattering of the code and reducing code size
and easy maintainability.

BUG=545968

Review URL: https://codereview.chromium.org/1413233003

Cr-Commit-Position: refs/heads/master@{#357524}

3 files changed, 189 insertions, 612 deletions

diff --git a/sync/internal_api/public/base/model_type.h b/sync/internal_api/public/base/model_type.h
index 383135b..5d353fd 100644
--- a/sync/internal_api/public/base/model_type.h
+++ b/sync/internal_api/public/base/model_type.h
@@ -36,6 +36,10 @@ namespace syncer {
 
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.sync
+
+// |kModelTypeInfoMap| struct entries are in the same order as their definition
+// in ModelType enum. Don't forget to update the |kModelTypeInfoMap| struct in
+// model_type.cc when you make changes in ModelType enum.
 enum ModelType {
   // Object type unknown.  Objects may transition through
   // the unknown state during their initial creation, before
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index 3ef7bac..1131249 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -25,6 +25,110 @@
 
 namespace syncer {
 
+struct ModelTypeInfo {
+  const ModelType model_type;
+  const char* const notification_type;  // Model Type notification string.
+  const char* const root_tag;           // Root tag for Model Type
+  const char* const model_type_string;  // String value for Model Type
+  const int specifics_field_number;     // SpecificsFieldNumber for Model Type
+  // Histogram value should be unique for the Model Type, Existing histogram
+  // values should never be modified without updating "SyncModelTypes" enum in
+  // histograms.xml to maintain backward compatibility.
+  const int model_type_histogram_val;
+};
+
+// Below struct entries are in the same order as their definition in the
+// ModelType enum. Don't forget to update the ModelType enum when you make
+// changes to this list.
+const ModelTypeInfo kModelTypeInfoMap[] = {
+    {UNSPECIFIED, "", "", "Unspecified", -1, 0},
+    {TOP_LEVEL_FOLDER, "", "", "Top Level Folder", -1, 1},
+    {BOOKMARKS, "BOOKMARK", "bookmarks", "Bookmarks",
+     sync_pb::EntitySpecifics::kBookmarkFieldNumber, 2},
+    {PREFERENCES, "PREFERENCE", "preferences", "Preferences",
+     sync_pb::EntitySpecifics::kPreferenceFieldNumber, 3},
+    {PASSWORDS, "PASSWORD", "passwords", "Passwords",
+     sync_pb::EntitySpecifics::kPasswordFieldNumber, 4},
+    {AUTOFILL_PROFILE, "AUTOFILL_PROFILE", "autofill_profiles",
+     "Autofill Profiles", sync_pb::EntitySpecifics::kAutofillProfileFieldNumber,
+     5},
+    {AUTOFILL, "AUTOFILL", "autofill", "Autofill",
+     sync_pb::EntitySpecifics::kAutofillFieldNumber, 6},
+    {AUTOFILL_WALLET_DATA, "AUTOFILL_WALLET", "autofill_wallet",
+     "Autofill Wallet", sync_pb::EntitySpecifics::kAutofillWalletFieldNumber,
+     34},
+    {AUTOFILL_WALLET_METADATA, "AUTOFILL_WALLET_METADATA",
+     "autofill_wallet_metadata", "Autofill Wallet Metadata",
+     sync_pb::EntitySpecifics::kWalletMetadataFieldNumber, 35},
+    {THEMES, "THEME", "themes", "Themes",
+     sync_pb::EntitySpecifics::kThemeFieldNumber, 7},
+    {TYPED_URLS, "TYPED_URL", "typed_urls", "Typed URLs",
+     sync_pb::EntitySpecifics::kTypedUrlFieldNumber, 8},
+    {EXTENSIONS, "EXTENSION", "extensions", "Extensions",
+     sync_pb::EntitySpecifics::kExtensionFieldNumber, 9},
+    {SEARCH_ENGINES, "SEARCH_ENGINE", "search_engines", "Search Engines",
+     sync_pb::EntitySpecifics::kSearchEngineFieldNumber, 10},
+    {SESSIONS, "SESSION", "sessions", "Sessions",
+     sync_pb::EntitySpecifics::kSessionFieldNumber, 11},
+    {APPS, "APP", "apps", "Apps", sync_pb::EntitySpecifics::kAppFieldNumber,
+     12},
+    {APP_SETTINGS, "APP_SETTING", "app_settings", "App settings",
+     sync_pb::EntitySpecifics::kAppSettingFieldNumber, 13},
+    {EXTENSION_SETTINGS, "EXTENSION_SETTING", "extension_settings",
+     "Extension settings",
+     sync_pb::EntitySpecifics::kExtensionSettingFieldNumber, 14},
+    {APP_NOTIFICATIONS, "APP_NOTIFICATION", "app_notifications",
+     "App Notifications", sync_pb::EntitySpecifics::kAppNotificationFieldNumber,
+     15},
+    {HISTORY_DELETE_DIRECTIVES, "HISTORY_DELETE_DIRECTIVE",
+     "history_delete_directives", "History Delete Directives",
+     sync_pb::EntitySpecifics::kHistoryDeleteDirectiveFieldNumber, 16},
+    {SYNCED_NOTIFICATIONS, "SYNCED_NOTIFICATION", "synced_notifications",
+     "Synced Notifications",
+     sync_pb::EntitySpecifics::kSyncedNotificationFieldNumber, 20},
+    {SYNCED_NOTIFICATION_APP_INFO, "SYNCED_NOTIFICATION_APP_INFO",
+     "synced_notification_app_info", "Synced Notification App Info",
+     sync_pb::EntitySpecifics::kSyncedNotificationAppInfoFieldNumber, 31},
+    {DICTIONARY, "DICTIONARY", "dictionary", "Dictionary",
+     sync_pb::EntitySpecifics::kDictionaryFieldNumber, 22},
+    {FAVICON_IMAGES, "FAVICON_IMAGE", "favicon_images", "Favicon Images",
+     sync_pb::EntitySpecifics::kFaviconImageFieldNumber, 23},
+    {FAVICON_TRACKING, "FAVICON_TRACKING", "favicon_tracking",
+     "Favicon Tracking", sync_pb::EntitySpecifics::kFaviconTrackingFieldNumber,
+     24},
+    {DEVICE_INFO, "DEVICE_INFO", "device_info", "Device Info",
+     sync_pb::EntitySpecifics::kDeviceInfoFieldNumber, 18},
+    {PRIORITY_PREFERENCES, "PRIORITY_PREFERENCE", "priority_preferences",
+     "Priority Preferences",
+     sync_pb::EntitySpecifics::kPriorityPreferenceFieldNumber, 21},
+    {SUPERVISED_USER_SETTINGS, "MANAGED_USER_SETTING", "managed_user_settings",
+     "Managed User Settings",
+     sync_pb::EntitySpecifics::kManagedUserSettingFieldNumber, 26},
+    {SUPERVISED_USERS, "MANAGED_USER", "managed_users", "Managed Users",
+     sync_pb::EntitySpecifics::kManagedUserFieldNumber, 27},
+    {SUPERVISED_USER_SHARED_SETTINGS, "MANAGED_USER_SHARED_SETTING",
+     "managed_user_shared_settings", "Managed User Shared Settings",
+     sync_pb::EntitySpecifics::kManagedUserSharedSettingFieldNumber, 30},
+    {ARTICLES, "ARTICLE", "articles", "Articles",
+     sync_pb::EntitySpecifics::kArticleFieldNumber, 28},
+    {APP_LIST, "APP_LIST", "app_list", "App List",
+     sync_pb::EntitySpecifics::kAppListFieldNumber, 29},
+    {WIFI_CREDENTIALS, "WIFI_CREDENTIAL", "wifi_credentials",
+     "WiFi Credentials", sync_pb::EntitySpecifics::kWifiCredentialFieldNumber,
+     32},
+    {SUPERVISED_USER_WHITELISTS, "MANAGED_USER_WHITELIST",
+     "managed_user_whitelists", "Managed User Whitelists",
+     sync_pb::EntitySpecifics::kManagedUserWhitelistFieldNumber, 33},
+    {PROXY_TABS, "", "", "Tabs", -1, 25},
+    {NIGORI, "NIGORI", "nigori", "Encryption keys",
+     sync_pb::EntitySpecifics::kNigoriFieldNumber, 17},
+    {EXPERIMENTS, "EXPERIMENTS", "experiments", "Experiments",
+     sync_pb::EntitySpecifics::kExperimentsFieldNumber, 19},
+};
+
+static_assert(arraysize(kModelTypeInfoMap) == MODEL_TYPE_COUNT,
+              "kModelTypeInfoMap should have MODEL_TYPE_COUNT elements");
+
 // Notes:
 // 1) This list must contain exactly the same elements as the set returned by
 //    UserSelectableTypes().
@@ -171,77 +275,10 @@ ModelType GetModelTypeFromSpecificsFieldNumber(int field_number) {
 int GetSpecificsFieldNumberFromModelType(ModelType model_type) {
   DCHECK(ProtocolTypes().Has(model_type))
       << "Only protocol types have field values.";
-  switch (model_type) {
-    case BOOKMARKS:
-      return sync_pb::EntitySpecifics::kBookmarkFieldNumber;
-    case PASSWORDS:
-      return sync_pb::EntitySpecifics::kPasswordFieldNumber;
-    case PREFERENCES:
-      return sync_pb::EntitySpecifics::kPreferenceFieldNumber;
-    case AUTOFILL:
-      return sync_pb::EntitySpecifics::kAutofillFieldNumber;
-    case AUTOFILL_PROFILE:
-      return sync_pb::EntitySpecifics::kAutofillProfileFieldNumber;
-    case AUTOFILL_WALLET_DATA:
-      return sync_pb::EntitySpecifics::kAutofillWalletFieldNumber;
-    case AUTOFILL_WALLET_METADATA:
-      return sync_pb::EntitySpecifics::kWalletMetadataFieldNumber;
-    case THEMES:
-      return sync_pb::EntitySpecifics::kThemeFieldNumber;
-    case TYPED_URLS:
-      return sync_pb::EntitySpecifics::kTypedUrlFieldNumber;
-    case EXTENSIONS:
-      return sync_pb::EntitySpecifics::kExtensionFieldNumber;
-    case NIGORI:
-      return sync_pb::EntitySpecifics::kNigoriFieldNumber;
-    case SEARCH_ENGINES:
-      return sync_pb::EntitySpecifics::kSearchEngineFieldNumber;
-    case SESSIONS:
-      return sync_pb::EntitySpecifics::kSessionFieldNumber;
-    case APPS:
-      return sync_pb::EntitySpecifics::kAppFieldNumber;
-    case APP_LIST:
-      return sync_pb::EntitySpecifics::kAppListFieldNumber;
-    case APP_SETTINGS:
-      return sync_pb::EntitySpecifics::kAppSettingFieldNumber;
-    case EXTENSION_SETTINGS:
-      return sync_pb::EntitySpecifics::kExtensionSettingFieldNumber;
-    case APP_NOTIFICATIONS:
-      return sync_pb::EntitySpecifics::kAppNotificationFieldNumber;
-    case HISTORY_DELETE_DIRECTIVES:
-      return sync_pb::EntitySpecifics::kHistoryDeleteDirectiveFieldNumber;
-    case SYNCED_NOTIFICATIONS:
-      return sync_pb::EntitySpecifics::kSyncedNotificationFieldNumber;
-    case SYNCED_NOTIFICATION_APP_INFO:
-      return sync_pb::EntitySpecifics::kSyncedNotificationAppInfoFieldNumber;
-    case DEVICE_INFO:
-      return sync_pb::EntitySpecifics::kDeviceInfoFieldNumber;
-    case EXPERIMENTS:
-      return sync_pb::EntitySpecifics::kExperimentsFieldNumber;
-    case PRIORITY_PREFERENCES:
-      return sync_pb::EntitySpecifics::kPriorityPreferenceFieldNumber;
-    case DICTIONARY:
-      return sync_pb::EntitySpecifics::kDictionaryFieldNumber;
-    case FAVICON_IMAGES:
-      return sync_pb::EntitySpecifics::kFaviconImageFieldNumber;
-    case FAVICON_TRACKING:
-      return sync_pb::EntitySpecifics::kFaviconTrackingFieldNumber;
-    case SUPERVISED_USER_SETTINGS:
-      return sync_pb::EntitySpecifics::kManagedUserSettingFieldNumber;
-    case SUPERVISED_USERS:
-      return sync_pb::EntitySpecifics::kManagedUserFieldNumber;
-    case SUPERVISED_USER_SHARED_SETTINGS:
-      return sync_pb::EntitySpecifics::kManagedUserSharedSettingFieldNumber;
-    case SUPERVISED_USER_WHITELISTS:
-      return sync_pb::EntitySpecifics::kManagedUserWhitelistFieldNumber;
-    case ARTICLES:
-      return sync_pb::EntitySpecifics::kArticleFieldNumber;
-    case WIFI_CREDENTIALS:
-      return sync_pb::EntitySpecifics::kWifiCredentialFieldNumber;
-    default:
-      NOTREACHED() << "No known extension for model type.";
-      return 0;
-  }
+  if (ProtocolTypes().Has(model_type))
+    return kModelTypeInfoMap[model_type].specifics_field_number;
+  NOTREACHED() << "No known extension for model type.";
+  return 0;
 }
 
 FullModelTypeSet ToFullModelTypeSet(ModelTypeSet in) {
@@ -534,82 +571,8 @@ const char* ModelTypeToString(ModelType model_type) {
   // This is used in serialization routines as well as for displaying debug
   // information.  Do not attempt to change these string values unless you know
   // what you're doing.
-  switch (model_type) {
-    case TOP_LEVEL_FOLDER:
-      return "Top Level Folder";
-    case UNSPECIFIED:
-      return "Unspecified";
-    case BOOKMARKS:
-      return "Bookmarks";
-    case PREFERENCES:
-      return "Preferences";
-    case PASSWORDS:
-      return "Passwords";
-    case AUTOFILL:
-      return "Autofill";
-    case THEMES:
-      return "Themes";
-    case TYPED_URLS:
-      return "Typed URLs";
-    case EXTENSIONS:
-      return "Extensions";
-    case NIGORI:
-      return "Encryption keys";
-    case SEARCH_ENGINES:
-      return "Search Engines";
-    case SESSIONS:
-      return "Sessions";
-    case APPS:
-      return "Apps";
-    case APP_LIST:
-      return "App List";
-    case AUTOFILL_PROFILE:
-      return "Autofill Profiles";
-    case APP_SETTINGS:
-      return "App settings";
-    case EXTENSION_SETTINGS:
-      return "Extension settings";
-    case APP_NOTIFICATIONS:
-      return "App Notifications";
-    case HISTORY_DELETE_DIRECTIVES:
-      return "History Delete Directives";
-    case SYNCED_NOTIFICATIONS:
-      return "Synced Notifications";
-    case SYNCED_NOTIFICATION_APP_INFO:
-      return "Synced Notification App Info";
-    case DEVICE_INFO:
-      return "Device Info";
-    case EXPERIMENTS:
-      return "Experiments";
-    case PRIORITY_PREFERENCES:
-      return "Priority Preferences";
-    case DICTIONARY:
-      return "Dictionary";
-    case FAVICON_IMAGES:
-      return "Favicon Images";
-    case FAVICON_TRACKING:
-      return "Favicon Tracking";
-    case SUPERVISED_USER_SETTINGS:
-      return "Managed User Settings";
-    case SUPERVISED_USERS:
-      return "Managed Users";
-    case SUPERVISED_USER_SHARED_SETTINGS:
-      return "Managed User Shared Settings";
-    case SUPERVISED_USER_WHITELISTS:
-      return "Managed User Whitelists";
-    case ARTICLES:
-      return "Articles";
-    case WIFI_CREDENTIALS:
-      return "WiFi Credentials";
-    case PROXY_TABS:
-      return "Tabs";
-    case AUTOFILL_WALLET_DATA:
-      return "Autofill Wallet";
-    case AUTOFILL_WALLET_METADATA:
-      return "Autofill Wallet Metadata";
-    default:
-      break;
-  }
+  if (model_type >= UNSPECIFIED && model_type < MODEL_TYPE_COUNT)
+    return kModelTypeInfoMap[model_type].model_type_string;
   NOTREACHED() << "No known extension for model type.";
   return "INVALID";
 }
@@ -621,83 +584,8 @@ const char* ModelTypeToString(ModelType model_type) {
 // Don't forget to update the "SyncModelTypes" enum in histograms.xml when you
 // make changes to this list.
 int ModelTypeToHistogramInt(ModelType model_type) {
-  switch (model_type) {
-    case UNSPECIFIED:
-      return 0;
-    case TOP_LEVEL_FOLDER:
-      return 1;
-    case BOOKMARKS:
-      return 2;
-    case PREFERENCES:
-      return 3;
-    case PASSWORDS:
-      return 4;
-    case AUTOFILL_PROFILE:
-      return 5;
-    case AUTOFILL:
-      return 6;
-    case THEMES:
-      return 7;
-    case TYPED_URLS:
-      return 8;
-    case EXTENSIONS:
-      return 9;
-    case SEARCH_ENGINES:
-      return 10;
-    case SESSIONS:
-      return 11;
-    case APPS:
-      return 12;
-    case APP_SETTINGS:
-      return 13;
-    case EXTENSION_SETTINGS:
-      return 14;
-    case APP_NOTIFICATIONS:
-      return 15;
-    case HISTORY_DELETE_DIRECTIVES:
-      return 16;
-    case NIGORI:
-      return 17;
-    case DEVICE_INFO:
-      return 18;
-    case EXPERIMENTS:
-      return 19;
-    case SYNCED_NOTIFICATIONS:
-      return 20;
-    case PRIORITY_PREFERENCES:
-      return 21;
-    case DICTIONARY:
-      return 22;
-    case FAVICON_IMAGES:
-      return 23;
-    case FAVICON_TRACKING:
-      return 24;
-    case PROXY_TABS:
-      return 25;
-    case SUPERVISED_USER_SETTINGS:
-      return 26;
-    case SUPERVISED_USERS:
-      return 27;
-    case ARTICLES:
-      return 28;
-    case APP_LIST:
-      return 29;
-    case SUPERVISED_USER_SHARED_SETTINGS:
-      return 30;
-    case SYNCED_NOTIFICATION_APP_INFO:
-      return 31;
-    case WIFI_CREDENTIALS:
-      return 32;
-    case SUPERVISED_USER_WHITELISTS:
-      return 33;
-    case AUTOFILL_WALLET_DATA:
-      return 34;
-    case AUTOFILL_WALLET_METADATA:
-      return 35;
-    // Silence a compiler warning.
-    case MODEL_TYPE_COUNT:
-      return 0;
-  }
+  if (model_type >= UNSPECIFIED && model_type < MODEL_TYPE_COUNT)
+    return kModelTypeInfoMap[model_type].model_type_histogram_val;
   return 0;
 }
 
@@ -729,77 +617,15 @@ ModelType ModelTypeFromValue(const base::Value& value) {
 }
 
 ModelType ModelTypeFromString(const std::string& model_type_string) {
-  if (model_type_string == "Bookmarks")
-    return BOOKMARKS;
-  else if (model_type_string == "Preferences")
-    return PREFERENCES;
-  else if (model_type_string == "Passwords")
-    return PASSWORDS;
-  else if (model_type_string == "Autofill")
-    return AUTOFILL;
-  else if (model_type_string == "Autofill Profiles")
-    return AUTOFILL_PROFILE;
-  else if (model_type_string == "Autofill Wallet")
-    return AUTOFILL_WALLET_DATA;
-  else if (model_type_string == "Autofill Wallet Metadata")
-    return AUTOFILL_WALLET_METADATA;
-  else if (model_type_string == "Themes")
-    return THEMES;
-  else if (model_type_string == "Typed URLs")
-    return TYPED_URLS;
-  else if (model_type_string == "Extensions")
-    return EXTENSIONS;
-  else if (model_type_string == "Encryption keys")
-    return NIGORI;
-  else if (model_type_string == "Search Engines")
-    return SEARCH_ENGINES;
-  else if (model_type_string == "Sessions")
-    return SESSIONS;
-  else if (model_type_string == "Apps")
-    return APPS;
-  else if (model_type_string == "App List")
-    return APP_LIST;
-  else if (model_type_string == "App settings")
-    return APP_SETTINGS;
-  else if (model_type_string == "Extension settings")
-    return EXTENSION_SETTINGS;
-  else if (model_type_string == "App Notifications")
-    return APP_NOTIFICATIONS;
-  else if (model_type_string == "History Delete Directives")
-    return HISTORY_DELETE_DIRECTIVES;
-  else if (model_type_string == "Synced Notifications")
-    return SYNCED_NOTIFICATIONS;
-  else if (model_type_string == "Synced Notification App Info")
-    return SYNCED_NOTIFICATION_APP_INFO;
-  else if (model_type_string == "Device Info")
-    return DEVICE_INFO;
-  else if (model_type_string == "Experiments")
-    return EXPERIMENTS;
-  else if (model_type_string == "Priority Preferences")
-    return PRIORITY_PREFERENCES;
-  else if (model_type_string == "Dictionary")
-    return DICTIONARY;
-  else if (model_type_string == "Favicon Images")
-    return FAVICON_IMAGES;
-  else if (model_type_string == "Favicon Tracking")
-    return FAVICON_TRACKING;
-  else if (model_type_string == "Managed User Settings")
-    return SUPERVISED_USER_SETTINGS;
-  else if (model_type_string == "Managed Users")
-    return SUPERVISED_USERS;
-  else if (model_type_string == "Managed User Shared Settings")
-    return SUPERVISED_USER_SHARED_SETTINGS;
-  else if (model_type_string == "Managed User Whitelists")
-    return SUPERVISED_USER_WHITELISTS;
-  else if (model_type_string == "Articles")
-    return ARTICLES;
-  else if (model_type_string == "WiFi Credentials")
-    return WIFI_CREDENTIALS;
-  else if (model_type_string == "Tabs")
-    return PROXY_TABS;
-  else
-    NOTREACHED() << "No known model type corresponding to "
-                 << model_type_string << ".";
+  if (model_type_string != "Unspecified" &&
+      model_type_string != "Top Level Folder") {
+    for (size_t i = 0; i < arraysize(kModelTypeInfoMap); ++i) {
+      if (kModelTypeInfoMap[i].model_type_string == model_type_string)
+        return kModelTypeInfoMap[i].model_type;
+    }
+  }
+  NOTREACHED() << "No known model type corresponding to " << model_type_string
+               << ".";
   return UNSPECIFIED;
 }
 
@@ -860,229 +686,19 @@ ModelTypeSet ModelTypeSetFromValue(const base::ListValue& value) {
 // NOTE: Proxy types should return empty strings (so that we don't NOTREACHED
 // in tests when we verify they have no root node).
 std::string ModelTypeToRootTag(ModelType type) {
-  switch (type) {
-    case BOOKMARKS:
-      return "google_chrome_bookmarks";
-    case PREFERENCES:
-      return "google_chrome_preferences";
-    case PASSWORDS:
-      return "google_chrome_passwords";
-    case AUTOFILL:
-      return "google_chrome_autofill";
-    case THEMES:
-      return "google_chrome_themes";
-    case TYPED_URLS:
-      return "google_chrome_typed_urls";
-    case EXTENSIONS:
-      return "google_chrome_extensions";
-    case NIGORI:
-      return "google_chrome_nigori";
-    case SEARCH_ENGINES:
-      return "google_chrome_search_engines";
-    case SESSIONS:
-      return "google_chrome_sessions";
-    case APPS:
-      return "google_chrome_apps";
-    case APP_LIST:
-      return "google_chrome_app_list";
-    case AUTOFILL_PROFILE:
-      return "google_chrome_autofill_profiles";
-    case AUTOFILL_WALLET_DATA:
-      return "google_chrome_autofill_wallet";
-    case AUTOFILL_WALLET_METADATA:
-      return "google_chrome_autofill_wallet_metadata";
-    case APP_SETTINGS:
-      return "google_chrome_app_settings";
-    case EXTENSION_SETTINGS:
-      return "google_chrome_extension_settings";
-    case APP_NOTIFICATIONS:
-      return "google_chrome_app_notifications";
-    case HISTORY_DELETE_DIRECTIVES:
-      return "google_chrome_history_delete_directives";
-    case SYNCED_NOTIFICATIONS:
-      return "google_chrome_synced_notifications";
-    case SYNCED_NOTIFICATION_APP_INFO:
-      return "google_chrome_synced_notification_app_info";
-    case DEVICE_INFO:
-      return "google_chrome_device_info";
-    case EXPERIMENTS:
-      return "google_chrome_experiments";
-    case PRIORITY_PREFERENCES:
-      return "google_chrome_priority_preferences";
-    case DICTIONARY:
-      return "google_chrome_dictionary";
-    case FAVICON_IMAGES:
-      return "google_chrome_favicon_images";
-    case FAVICON_TRACKING:
-      return "google_chrome_favicon_tracking";
-    case SUPERVISED_USER_SETTINGS:
-      return "google_chrome_managed_user_settings";
-    case SUPERVISED_USERS:
-      return "google_chrome_managed_users";
-    case SUPERVISED_USER_SHARED_SETTINGS:
-      return "google_chrome_managed_user_shared_settings";
-    case SUPERVISED_USER_WHITELISTS:
-      return "google_chrome_managed_user_whitelists";
-    case ARTICLES:
-      return "google_chrome_articles";
-    case WIFI_CREDENTIALS:
-      return "google_chrome_wifi_credentials";
-    case PROXY_TABS:
-      return std::string();
-    default:
-      break;
-  }
+  if (IsProxyType(type))
+    return std::string();
+  if (IsRealDataType(type))
+    return "google_chrome_" + std::string(kModelTypeInfoMap[type].root_tag);
   NOTREACHED() << "No known extension for model type.";
   return "INVALID";
 }
 
-// TODO(akalin): Figure out a better way to do these mappings.
-// Note: Do not include proxy types in this list. They should never receive
-// or trigger notifications.
-namespace {
-const char kBookmarkNotificationType[] = "BOOKMARK";
-const char kPreferenceNotificationType[] = "PREFERENCE";
-const char kPasswordNotificationType[] = "PASSWORD";
-const char kAutofillNotificationType[] = "AUTOFILL";
-const char kThemeNotificationType[] = "THEME";
-const char kTypedUrlNotificationType[] = "TYPED_URL";
-const char kExtensionNotificationType[] = "EXTENSION";
-const char kExtensionSettingNotificationType[] = "EXTENSION_SETTING";
-const char kNigoriNotificationType[] = "NIGORI";
-const char kAppSettingNotificationType[] = "APP_SETTING";
-const char kAppNotificationType[] = "APP";
-const char kAppListNotificationType[] = "APP_LIST";
-const char kSearchEngineNotificationType[] = "SEARCH_ENGINE";
-const char kSessionNotificationType[] = "SESSION";
-const char kAutofillProfileNotificationType[] = "AUTOFILL_PROFILE";
-const char kAutofillWalletMetadataNotificationType[] =
-    "AUTOFILL_WALLET_METADATA";
-const char kAutofillWalletNotificationType[] = "AUTOFILL_WALLET";
-const char kAppNotificationNotificationType[] = "APP_NOTIFICATION";
-const char kHistoryDeleteDirectiveNotificationType[] =
-    "HISTORY_DELETE_DIRECTIVE";
-const char kSyncedNotificationType[] = "SYNCED_NOTIFICATION";
-const char kSyncedNotificationAppInfoType[] = "SYNCED_NOTIFICATION_APP_INFO";
-const char kDeviceInfoNotificationType[] = "DEVICE_INFO";
-const char kExperimentsNotificationType[] = "EXPERIMENTS";
-const char kPriorityPreferenceNotificationType[] = "PRIORITY_PREFERENCE";
-const char kDictionaryNotificationType[] = "DICTIONARY";
-const char kFaviconImageNotificationType[] = "FAVICON_IMAGE";
-const char kFaviconTrackingNotificationType[] = "FAVICON_TRACKING";
-const char kSupervisedUserSettingNotificationType[] = "MANAGED_USER_SETTING";
-const char kSupervisedUserNotificationType[] = "MANAGED_USER";
-const char kSupervisedUserSharedSettingNotificationType[] =
-    "MANAGED_USER_SHARED_SETTING";
-const char kSupervisedUserWhitelistNotificationType[] =
-    "MANAGED_USER_WHITELIST";
-const char kArticleNotificationType[] = "ARTICLE";
-const char kWifiCredentialNotificationType[] = "WIFI_CREDENTIAL";
-}  // namespace
-
 bool RealModelTypeToNotificationType(ModelType model_type,
                                      std::string* notification_type) {
-  switch (model_type) {
-    case BOOKMARKS:
-      *notification_type = kBookmarkNotificationType;
-      return true;
-    case PREFERENCES:
-      *notification_type = kPreferenceNotificationType;
-      return true;
-    case PASSWORDS:
-      *notification_type = kPasswordNotificationType;
-      return true;
-    case AUTOFILL:
-      *notification_type = kAutofillNotificationType;
-      return true;
-    case THEMES:
-      *notification_type = kThemeNotificationType;
-      return true;
-    case TYPED_URLS:
-      *notification_type = kTypedUrlNotificationType;
-      return true;
-    case EXTENSIONS:
-      *notification_type = kExtensionNotificationType;
-      return true;
-    case NIGORI:
-      *notification_type = kNigoriNotificationType;
-      return true;
-    case APP_SETTINGS:
-      *notification_type = kAppSettingNotificationType;
-      return true;
-    case APPS:
-      *notification_type = kAppNotificationType;
-      return true;
-    case APP_LIST:
-      *notification_type = kAppListNotificationType;
-      return true;
-    case SEARCH_ENGINES:
-      *notification_type = kSearchEngineNotificationType;
-      return true;
-    case SESSIONS:
-      *notification_type = kSessionNotificationType;
-      return true;
-    case AUTOFILL_PROFILE:
-      *notification_type = kAutofillProfileNotificationType;
-      return true;
-    case AUTOFILL_WALLET_DATA:
-      *notification_type = kAutofillWalletNotificationType;
-      return true;
-    case AUTOFILL_WALLET_METADATA:
-      *notification_type = kAutofillWalletMetadataNotificationType;
-      return true;
-    case EXTENSION_SETTINGS:
-      *notification_type = kExtensionSettingNotificationType;
-      return true;
-    case APP_NOTIFICATIONS:
-      *notification_type = kAppNotificationNotificationType;
-      return true;
-    case HISTORY_DELETE_DIRECTIVES:
-      *notification_type = kHistoryDeleteDirectiveNotificationType;
-      return true;
-    case SYNCED_NOTIFICATIONS:
-      *notification_type = kSyncedNotificationType;
-      return true;
-    case SYNCED_NOTIFICATION_APP_INFO:
-      *notification_type = kSyncedNotificationAppInfoType;
-      return true;
-    case DEVICE_INFO:
-      *notification_type = kDeviceInfoNotificationType;
-      return true;
-    case EXPERIMENTS:
-      *notification_type = kExperimentsNotificationType;
-      return true;
-    case PRIORITY_PREFERENCES:
-      *notification_type = kPriorityPreferenceNotificationType;
-      return true;
-    case DICTIONARY:
-      *notification_type = kDictionaryNotificationType;
-      return true;
-    case FAVICON_IMAGES:
-      *notification_type = kFaviconImageNotificationType;
-      return true;
-    case FAVICON_TRACKING:
-      *notification_type = kFaviconTrackingNotificationType;
-      return true;
-    case SUPERVISED_USER_SETTINGS:
-      *notification_type = kSupervisedUserSettingNotificationType;
-      return true;
-    case SUPERVISED_USERS:
-      *notification_type = kSupervisedUserNotificationType;
-      return true;
-    case SUPERVISED_USER_SHARED_SETTINGS:
-      *notification_type = kSupervisedUserSharedSettingNotificationType;
-      return true;
-    case SUPERVISED_USER_WHITELISTS:
-      *notification_type = kSupervisedUserWhitelistNotificationType;
-      return true;
-    case ARTICLES:
-      *notification_type = kArticleNotificationType;
-      return true;
-    case WIFI_CREDENTIALS:
-      *notification_type = kWifiCredentialNotificationType;
-      return true;
-    default:
-      break;
+  if (ProtocolTypes().Has(model_type)) {
+    *notification_type = kModelTypeInfoMap[model_type].notification_type;
+    return true;
   }
   notification_type->clear();
   return false;
@@ -1090,106 +706,15 @@ bool RealModelTypeToNotificationType(ModelType model_type,
 
 bool NotificationTypeToRealModelType(const std::string& notification_type,
                                      ModelType* model_type) {
-  if (notification_type == kBookmarkNotificationType) {
-    *model_type = BOOKMARKS;
-    return true;
-  } else if (notification_type == kPreferenceNotificationType) {
-    *model_type = PREFERENCES;
-    return true;
-  } else if (notification_type == kPasswordNotificationType) {
-    *model_type = PASSWORDS;
-    return true;
-  } else if (notification_type == kAutofillNotificationType) {
-    *model_type = AUTOFILL;
-    return true;
-  } else if (notification_type == kThemeNotificationType) {
-    *model_type = THEMES;
-    return true;
-  } else if (notification_type == kTypedUrlNotificationType) {
-    *model_type = TYPED_URLS;
-    return true;
-  } else if (notification_type == kExtensionNotificationType) {
-    *model_type = EXTENSIONS;
-    return true;
-  } else if (notification_type == kNigoriNotificationType) {
-    *model_type = NIGORI;
-    return true;
-  } else if (notification_type == kAppNotificationType) {
-    *model_type = APPS;
-    return true;
-  } else if (notification_type == kAppListNotificationType) {
-    *model_type = APP_LIST;
-    return true;
-  } else if (notification_type == kSearchEngineNotificationType) {
-    *model_type = SEARCH_ENGINES;
-    return true;
-  } else if (notification_type == kSessionNotificationType) {
-    *model_type = SESSIONS;
-    return true;
-  } else if (notification_type == kAutofillProfileNotificationType) {
-    *model_type = AUTOFILL_PROFILE;
-    return true;
-  } else if (notification_type == kAutofillWalletNotificationType) {
-    *model_type = AUTOFILL_WALLET_DATA;
-    return true;
-  } else if (notification_type == kAutofillWalletMetadataNotificationType) {
-    *model_type = AUTOFILL_WALLET_METADATA;
-    return true;
-  } else if (notification_type == kAppSettingNotificationType) {
-    *model_type = APP_SETTINGS;
-    return true;
-  } else if (notification_type == kExtensionSettingNotificationType) {
-    *model_type = EXTENSION_SETTINGS;
-    return true;
-  } else if (notification_type == kAppNotificationNotificationType) {
-    *model_type = APP_NOTIFICATIONS;
-    return true;
-  } else if (notification_type == kHistoryDeleteDirectiveNotificationType) {
-    *model_type = HISTORY_DELETE_DIRECTIVES;
-    return true;
-  } else if (notification_type == kSyncedNotificationType) {
-    *model_type = SYNCED_NOTIFICATIONS;
-    return true;
-  } else if (notification_type == kSyncedNotificationAppInfoType) {
-    *model_type = SYNCED_NOTIFICATION_APP_INFO;
-    return true;
-  } else if (notification_type == kDeviceInfoNotificationType) {
-    *model_type = DEVICE_INFO;
-    return true;
-  } else if (notification_type == kExperimentsNotificationType) {
-    *model_type = EXPERIMENTS;
-    return true;
-  } else if (notification_type == kPriorityPreferenceNotificationType) {
-    *model_type = PRIORITY_PREFERENCES;
-    return true;
-  } else if (notification_type == kDictionaryNotificationType) {
-    *model_type = DICTIONARY;
-    return true;
-  } else if (notification_type == kFaviconImageNotificationType) {
-    *model_type = FAVICON_IMAGES;
-    return true;
-  } else if (notification_type == kFaviconTrackingNotificationType) {
-    *model_type = FAVICON_TRACKING;
-    return true;
-  } else if (notification_type == kSupervisedUserSettingNotificationType) {
-    *model_type = SUPERVISED_USER_SETTINGS;
-    return true;
-  } else if (notification_type == kSupervisedUserNotificationType) {
-    *model_type = SUPERVISED_USERS;
-    return true;
-  } else if (notification_type ==
-      kSupervisedUserSharedSettingNotificationType) {
-    *model_type = SUPERVISED_USER_SHARED_SETTINGS;
-    return true;
-  } else if (notification_type == kSupervisedUserWhitelistNotificationType) {
-    *model_type = SUPERVISED_USER_WHITELISTS;
-    return true;
-  } else if (notification_type == kArticleNotificationType) {
-    *model_type = ARTICLES;
-    return true;
-  } else if (notification_type == kWifiCredentialNotificationType) {
-    *model_type = WIFI_CREDENTIALS;
-    return true;
+  if (notification_type.empty()) {
+    *model_type = UNSPECIFIED;
+    return false;
+  }
+  for (size_t i = 0; i < arraysize(kModelTypeInfoMap); ++i) {
+    if (kModelTypeInfoMap[i].notification_type == notification_type) {
+      *model_type = kModelTypeInfoMap[i].model_type;
+      return true;
+    }
   }
   *model_type = UNSPECIFIED;
   return false;
diff --git a/sync/syncable/model_type_unittest.cc b/sync/syncable/model_type_unittest.cc
index 05692c0..a60b7cf 100644
--- a/sync/syncable/model_type_unittest.cc
+++ b/sync/syncable/model_type_unittest.cc
@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
+#include "base/strings/string_util.h"
 #include "base/test/values_test_util.h"
 #include "base/values.h"
 #include "sync/protocol/sync.pb.h"
@@ -144,5 +145,52 @@ TEST_F(ModelTypeTest, DefaultFieldValues) {
   }
 }
 
+TEST_F(ModelTypeTest, ModelTypeToRootTagValues) {
+  ModelTypeSet all_types = ModelTypeSet::All();
+  for (ModelTypeSet::Iterator it = all_types.First(); it.Good(); it.Inc()) {
+    ModelType model_type = it.Get();
+    std::string root_tag = ModelTypeToRootTag(model_type);
+    if (IsProxyType(model_type)) {
+      EXPECT_EQ(root_tag, std::string());
+    } else if (IsRealDataType(model_type)) {
+      EXPECT_TRUE(base::StartsWith(root_tag, "google_chrome_",
+                                   base::CompareCase::INSENSITIVE_ASCII));
+    } else {
+      EXPECT_EQ(root_tag, "INVALID");
+    }
+  }
+}
+
+TEST_F(ModelTypeTest, ModelTypeStringMapping) {
+  ModelTypeSet all_types = ModelTypeSet::All();
+  for (ModelTypeSet::Iterator it = all_types.First(); it.Good(); it.Inc()) {
+    ModelType model_type = it.Get();
+    const char* model_type_string = ModelTypeToString(model_type);
+    ModelType converted_model_type = ModelTypeFromString(model_type_string);
+    if (IsRealDataType(model_type))
+      EXPECT_EQ(converted_model_type, model_type);
+    else
+      EXPECT_EQ(converted_model_type, UNSPECIFIED);
+  }
+}
+
+TEST_F(ModelTypeTest, ModelTypeNotificationTypeMapping) {
+  ModelTypeSet all_types = ModelTypeSet::All();
+  for (ModelTypeSet::Iterator it = all_types.First(); it.Good(); it.Inc()) {
+    ModelType model_type = it.Get();
+    std::string notification_type;
+    bool ret = RealModelTypeToNotificationType(model_type, &notification_type);
+    if (ret) {
+      ModelType notified_model_type;
+      EXPECT_TRUE(NotificationTypeToRealModelType(notification_type,
+                                                  &notified_model_type));
+      EXPECT_EQ(notified_model_type, model_type);
+    } else {
+      EXPECT_FALSE(ProtocolTypes().Has(model_type));
+      EXPECT_TRUE(notification_type.empty());
+    }
+  }
+}
+
 }  // namespace
 }  // namespace syncer