[Signin][Settings] Disable preference animations

Because this settings screen has preference changes that occur
quickly (but asynchronously) as the fragment loaded, the animations
appeared janky.

Tracking bug to find a better solution to this class of issues:
https://crbug.com/986401

Bug: 995668
Change-Id: Ic2cc2acffc94d67d0b9dffeea5a0e0d6deaff925
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1776595
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#692138}

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

@@ -133,6 +133,9 @@ public class AccountManagementFragment extends PreferenceFragmentCompat
         super.onActivityCreated(savedInstanceState);
 
         setDivider(null);
+
+        // Disable animations of preference changes (crbug.com/986401).
+        getListView().setItemAnimator(null);
     }
 
     @Override