[Signin][Android] Load accounts into IdentityManager before setting primary account

Changes order of calls in SigninManager - now it triggers an update to
the account list before setting the primary account. This way, the list
of accounts is available by the time the primary account is set.

Bug: 1095128, 1121479
Change-Id: Idc596f99e6899624284b9cc86bdf01320f16b954
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2416520Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808270}

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java

@@ -522,6 +522,11 @@ public class SigninManager
         // The user should not be already signed in
         assert !mIdentityManager.hasPrimaryAccount();
 
+        // Setting the primary account triggers observers which query accounts from IdentityManager.
+        // Reloading before setting the primary ensures they don't get an empty list of accounts.
+        mIdentityMutator.reloadAllAccountsFromSystemWithPrimaryAccount(
+                mSignInState.mCoreAccountInfo.getId());
+
         @ConsentLevel
         int consentLevel =
                 mSignInState.shouldTurnSyncOn() ? ConsentLevel.SYNC : ConsentLevel.NOT_REQUIRED;
@@ -551,9 +556,6 @@ public class SigninManager
             mSignInState.mCallback.onSignInComplete();
         }
 
-        // Trigger token requests via identity mutator.
-        reloadAllAccountsFromSystem();
-
         Log.d(TAG, "Signin completed.");
         mSignInState = null;
         notifyCallbacksWaitingForOperation();