Eliminate duplicate keys in pref xmls.

- Remove additional_system_update pref device_info page, we don't need
  it.
- Update keys in xml and Preference controller, and search index
  provider.
- Clean up in ScreenZoomPreference, it's anti-pattern to set fragment in
  constructor.
- Whitelist 2 that are super hard to remove.

Change-Id: Ibab6e2cb074513042a2ae007d9085aa64046eec8
Fixes: 67852637
Test: uniquePreferenceTest

tests/unit/src/com/android/settings/UniquePreferenceTest.java

@@ -54,10 +54,19 @@ public class UniquePreferenceTest {
     private static final String TAG = "UniquePreferenceTest";
     private static final List<String> SUPPORTED_PREF_TYPES = Arrays.asList(
             "Preference", "PreferenceCategory", "PreferenceScreen");
+    private static final List<String> WHITELISTED_DUPLICATE_KEYS = Arrays.asList(
+            "owner_info_settings",          // Lock screen message in security - multiple xml files
+                                            // contain this because security page is constructed by
+                                            // combining small xml chunks. Eventually the page
+                                            // should be formed as one single xml and this entry
+                                            // should be removed.
+
+            "dashboard_tile_placeholder"    // This is the placeholder pref for injecting dynamic
+                                            // tiles.
+            );
 
     private Context mContext;
 
-
     @Before
     public void setUp() {
         mContext = InstrumentationRegistry.getTargetContext();
@@ -148,7 +157,7 @@ public class UniquePreferenceTest {
                     nullKeyClasses.add(page.className);
                     continue;
                 }
-                if (uniqueKeys.contains(key)) {
+                if (uniqueKeys.contains(key) && !WHITELISTED_DUPLICATE_KEYS.contains(key)) {
                     Log.e(TAG, "Every preference key must unique; found " + nodeName
                             + " in " + page.className
                             + " at " + parser.getPositionDescription());