[s13n] Migrate SigninManagerAndroid's usage of...

[s13n] Migrate SigninManagerAndroid's usage of O2TSDelegateAndroid::ValidateAccounts to IdentityManager

This CL uses IdentityManager::LegacyReloadAccountsFromSystem that
calls O2TSDelegateAndroid::ValidateAccounts internally.

Bug: 905340
Change-Id: I7fc6f18ef59a88373a68ba0dee292e344a3af65e
Reviewed-on: https://chromium-review.googlesource.com/c/1469813Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: Miyoung Shin <myid.shin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632437}

chrome/browser/android/signin/signin_manager_android.cc

@@ -308,12 +308,8 @@ void SigninManagerAndroid::LogInSignedInUser(JNIEnv* env,
       IdentityManagerFactory::GetForProfile(profile_);
   // With the account consistency enabled let the account Reconcilor handles
   // everything.
-  ProfileOAuth2TokenService* token_service =
-      ProfileOAuth2TokenServiceFactory::GetForProfile(profile_);
-  const std::string& primary_acct = identity_manager->GetPrimaryAccountId();
-
-  static_cast<OAuth2TokenServiceDelegateAndroid*>(token_service->GetDelegate())
-      ->ValidateAccounts(primary_acct, true);
+  // TODO(https://crbug.com/930094): Determine the right long-term flow here.
+  identity_manager->LegacyReloadAccountsFromSystem();
 }
 
 jboolean SigninManagerAndroid::IsSigninAllowedByPolicy(