Fork SettingsDrawerActivity in Settings.

Settings app uses fragment classes from android framework,
which is deprecated as of P.
We need to switch to use fragment and associated classes to androidx.

Because Settings didn't support drawer feature since Android O,
we rename SettingsDrawerActivity to SettingsBaseActivity.

Before we migrate to fragment of androix,
we need to let SettingsBaseActivity extend FragmentActivity.

Test: make RunSettingsRoboTests
Bug: 110259478
Change-Id: Ifbf53f75f042da1618da16cf7837b70d298a9a14

src/com/android/settings/backup/BackupSettingsHelper.java

@@ -152,7 +152,6 @@ public class BackupSettingsHelper {
     }
 
     private Intent getIntentForDefaultBackupSettings() {
-        // Extra needed by {@link SettingsDrawerActivity} to show the back button navigation.
         return new Intent(mContext, PrivacySettingsActivity.class);
     }