Clean up pass on account_investigator_unittest.cc

This is a follow up of [1], from blundell@.

[1] https://crrev.com/c/1398041/3/components/signin/core/browser/account_investigator_unittest.cc#183

Bug=919482

Change-Id: I5dbca667c7c4c8152fab529df976eb1e04acb983
Reviewed-on: https://chromium-review.googlesource.com/c/1403156
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#621549}

components/signin/core/browser/account_investigator_unittest.cc

@@ -150,25 +150,23 @@ AccountInfo Account(const std::string& id) {
   return account;
 }
 
-AccountInfo Info(const std::string& id) {
-  AccountInfo info;
-  info.account_id = id;
-  return info;
-}
-
 // NOTE: IdentityTestEnvironment uses a prefix for generating gaia IDs:
 // "gaia_id_for_". For this reason, the tests prefix expected account IDs
 // used so that there is a match.
+
+const std::string kGaiaId1 = identity::GetTestGaiaIdForEmail("1@mail.com");
+const std::string kGaiaId2 = identity::GetTestGaiaIdForEmail("2@mail.com");
+const std::string kGaiaId3 = identity::GetTestGaiaIdForEmail("3@mail.com");
+
+const AccountInfo one(Account(kGaiaId1));
+const AccountInfo two(Account(kGaiaId2));
+const AccountInfo three(Account(kGaiaId3));
+
 const std::vector<AccountInfo> no_accounts{};
-const std::vector<AccountInfo> just_one{Account("gaia_id_for_1_mail.com")};
-const std::vector<AccountInfo> just_two{Account("gaia_id_for_2_mail.com")};
-const std::vector<AccountInfo> both{Account("gaia_id_for_1_mail.com"),
-                                    Account("gaia_id_for_2_mail.com")};
-const std::vector<AccountInfo> both_reversed{Account("gaia_id_for_2_mail.com"),
-                                             Account("gaia_id_for_1_mail.com")};
-
-const AccountInfo one(Info("gaia_id_for_1_mail.com"));
-const AccountInfo three(Info("gaia_id_for_3_mail.com"));
+const std::vector<AccountInfo> just_one{one};
+const std::vector<AccountInfo> just_two{two};
+const std::vector<AccountInfo> both{one, two};
+const std::vector<AccountInfo> both_reversed{two, one};
 
 TEST_F(AccountInvestigatorTest, CalculatePeriodicDelay) {
   const Time epoch;