[Android] Postpone validateAccountSettings until accounts are ready

This CL modifies SigninHelper.validateAccountSettings so that accounts
are accessed only after AccountManagerFacade cache is populated.
SigninHelper.validateAccountSettings is called early during startup,
so postponing this call should reduce the amount of time spent waiting
for accounts on UI thread.

Bug: 837374
Change-Id: Ica027806d9a329e08b880abec12dc0954c540e63
Reviewed-on: https://chromium-review.googlesource.com/c/1329247Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607221}

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

@@ -120,6 +120,13 @@ public class SigninHelper {
     }
 
     public void validateAccountSettings(boolean accountsChanged) {
+        // validateAccountsInternal accesses account list (to check whether account exists), so
+        // postpone the call until account list cache in AccountManagerFacade is ready.
+        AccountManagerFacade.get().runAfterCacheIsPopulated(
+                () -> validateAccountsInternal(accountsChanged));
+    }
+
+    private void validateAccountsInternal(boolean accountsChanged) {
         // Ensure System accounts have been seeded.
         mAccountTrackerService.checkAndSeedSystemAccounts();
         if (!accountsChanged) {
@@ -155,7 +162,7 @@ public class SigninHelper {
                     if (renamedAccount == null) {
                         mSigninManager.signOut(SignoutReason.ACCOUNT_REMOVED_FROM_DEVICE);
                     } else {
-                        validateAccountSettings(true);
+                        validateAccountsInternal(true);
                     }
                 }
             };
@@ -217,7 +224,7 @@ public class SigninHelper {
                 if (mProfileSyncService != null) {
                     mProfileSyncService.setSetupInProgress(false);
                 }
-                validateAccountSettings(true);
+                validateAccountsInternal(true);
             }
 
             @Override

components/signin/core/browser/android/java/src/org/chromium/components/signin/AccountManagerFacade.java

@@ -229,7 +229,6 @@ public class AccountManagerFacade {
      * @param runnable The callback to call after cache is populated. Invoked on the main thread.
      */
     @MainThread
-    @VisibleForTesting
     public void runAfterCacheIsPopulated(Runnable runnable) {
         ThreadUtils.assertOnUiThread();
         if (isCachePopulated()) {