Regroup and trim IdentityManager methods for account ID migration

Groups these related methods together and eliminates one method that
has no production callers.

Bug: 970295
Change-Id: I07c9f79862efcf94b28ad7c2571b0a33a77be316
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1729264Reviewed-by: Lowell Manners <lowell@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683112}

components/signin/public/identity_manager/identity_manager.cc

@@ -392,9 +392,19 @@ void IdentityManager::OnNetworkInitialized() {
   account_fetcher_service_->OnNetworkInitialized();
 }
 
-// static
-bool IdentityManager::IsAccountIdMigrationSupported() {
-  return AccountTrackerService::IsMigrationSupported();
+IdentityManager::AccountIdMigrationState
+IdentityManager::GetAccountIdMigrationState() const {
+  return static_cast<IdentityManager::AccountIdMigrationState>(
+      account_tracker_service_->GetMigrationState());
+}
+
+CoreAccountId IdentityManager::PickAccountIdForAccount(
+    const std::string& gaia,
+    const std::string& email) const {
+  // TODO(triploblastic@): Remove explicit conversion once
+  // primary_account_manager has been fixed to use CoreAccountId.
+  return CoreAccountId(
+      account_tracker_service_->PickAccountIdForAccount(gaia, email));
 }
 
 // static
@@ -413,21 +423,6 @@ void IdentityManager::RegisterProfilePrefs(PrefRegistrySimple* registry) {
 #endif
 }
 
-CoreAccountId IdentityManager::PickAccountIdForAccount(
-    const std::string& gaia,
-    const std::string& email) const {
-  // TODO(triploblastic@): Remove explicit conversion once
-  // primary_account_manager has been fixed to use CoreAccountId.
-  return CoreAccountId(
-      account_tracker_service_->PickAccountIdForAccount(gaia, email));
-}
-
-IdentityManager::AccountIdMigrationState
-IdentityManager::GetAccountIdMigrationState() const {
-  return static_cast<IdentityManager::AccountIdMigrationState>(
-      account_tracker_service_->GetMigrationState());
-}
-
 #if !defined(OS_IOS) && !defined(OS_ANDROID)
 void IdentityManager::DeprecatedLoadCredentialsForSupervisedUser(
     const CoreAccountId& primary_account_id) {

components/signin/public/identity_manager/identity_manager.h

@@ -394,22 +394,10 @@ class IdentityManager : public KeyedService,
   // initialized.
   void OnNetworkInitialized();
 
-  // Returns |true| if migration of the account ID from normalized email is
-  // supported for the current platform.
-  static bool IsAccountIdMigrationSupported();
-
-  // Registers per-install prefs used by this class.
-  static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);
-
-  // Registers per-profile prefs used by this class.
-  static void RegisterProfilePrefs(PrefRegistrySimple* registry);
-
-  // Picks the correct account_id for the specified account depending on the
-  // migration state.
-  // TODO(https://crbug.com/883272): Remove once all platform have migrated to
-  // the new account_id based on gaia (currently, only Chrome OS remains).
-  CoreAccountId PickAccountIdForAccount(const std::string& gaia,
-                                        const std::string& email) const;
+  // Methods related to migration of account IDs from email to Gaia ID.
+  // TODO(https://crbug.com/883272): Remove these once all platforms have
+  // migrated to the new account_id based on gaia (currently, only ChromeOS
+  // remains).
 
   // Possible values for the account ID migration state, needs to be kept in
   // sync with AccountTrackerService::AccountIdMigrationState.
@@ -420,9 +408,21 @@ class IdentityManager : public KeyedService,
     NUM_MIGRATION_STATES
   };
 
-  // Returns the currently saved state for the migration of accounts IDs.
+  // Returns the currently saved state of the migration of account IDs.
   AccountIdMigrationState GetAccountIdMigrationState() const;
 
+  // Picks the correct account_id for the specified account depending on the
+  // migration state.
+  CoreAccountId PickAccountIdForAccount(const std::string& gaia,
+                                        const std::string& email) const;
+
+  // Methods used only by embedder-level factory classes.
+
+  // Registers per-install prefs used by this class.
+  static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);
+  // Registers per-profile prefs used by this class.
+  static void RegisterProfilePrefs(PrefRegistrySimple* registry);
+
 #if !defined(OS_IOS) && !defined(OS_ANDROID)
   // Explicitly triggers the loading of accounts in the context of supervised
   // users.

components/signin/public/identity_manager/identity_manager_unittest.cc

@@ -2148,7 +2148,7 @@ TEST_F(IdentityManagerTest, AreRefreshTokensLoaded) {
 TEST_F(IdentityManagerTest, AccountIdMigration_DoneOnInitialization) {
   // Migration gets marked as DONE while initializing the AccountTrackerService
   // on platforms supporting account ID migration only.
-  if (IdentityManager::IsAccountIdMigrationSupported()) {
+  if (account_tracker()->IsMigrationSupported()) {
     EXPECT_EQ(identity_manager()->GetAccountIdMigrationState(),
               IdentityManager::AccountIdMigrationState::MIGRATION_DONE);
   } else {