[Signin][Android] Fix add account flow

Fixes "add account" flow in AccountManagementFragment that was broken by
https://crrev.com/c/1817607.
Before: Activity is finished right after the preference is clicked.
    Thus, isResumed check in createAddAccountIntent returns false and
    the intent is not started.
After: Activity is finished from createAddAccountIntent callback, so
    isResumed check passes.

Bug: 1036777
Change-Id: Ieaf443adf586eb1dd5949eca021ee9b499201bb1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1982556
Auto-Submit: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727751}

chrome/android/java/src/org/chromium/chrome/browser/settings/sync/AccountManagementFragment.java

@@ -318,19 +318,17 @@ public class AccountManagementFragment extends PreferenceFragmentCompat
 
                 if (intent != null) {
                     startActivity(intent);
-                    return;
+                } else {
+                    // AccountManagerFacade couldn't create intent, use SigninUtils to open settings
+                    // instead.
+                    SigninUtils.openSettingsForAllAccounts(getActivity());
                 }
 
-                // AccountManagerFacade couldn't create intent, use SigninUtils to open settings
-                // instead.
-                SigninUtils.openSettingsForAllAccounts(getActivity());
+                // Return to the last opened tab if triggered from the content area.
+                if (mGaiaServiceType != GAIAServiceType.GAIA_SERVICE_TYPE_NONE) {
+                    if (isAdded()) getActivity().finish();
+                }
             });
-
-            // Return to the last opened tab if triggered from the content area.
-            if (mGaiaServiceType != GAIAServiceType.GAIA_SERVICE_TYPE_NONE) {
-                if (isAdded()) getActivity().finish();
-            }
-
             return true;
         });
         addAccountPreference.setManagedPreferenceDelegate(preference -> !canAddAccounts());