Improve flicker when enter Security page

The flicker preferences are injected from external apps and the text
shifting is due to it needing time to load the icon from the content
uri. To avoid flicker, put a transparent icon as default to wait for
icon update.

Fixes: 189165518
Test: robotests & visual
Change-Id: I727eeefd5455711a53d3fd9ccd5356a15b9daae4

src/com/android/settings/dashboard/DashboardFeatureProviderImpl.java

@@ -360,6 +360,11 @@ public class DashboardFeatureProviderImpl implements DashboardFeatureProvider {
         // Icon provided by the content provider overrides any static icon.
         if (tile.getMetaData() != null
                 && tile.getMetaData().containsKey(META_DATA_PREFERENCE_ICON_URI)) {
+            // Set a transparent color before starting to fetch the real icon, this is necessary
+            // to avoid preference padding change.
+            setPreferenceIcon(preference, tile, forceRoundedIcon, mContext.getPackageName(),
+                    Icon.createWithResource(mContext, android.R.color.transparent));
+
             ThreadUtils.postOnBackgroundThread(() -> {
                 final Intent intent = tile.getIntent();
                 String packageName = null;