Move indexing into the Search Fragment

Cold start latency for Settings increased drastically
from the indexing of the Search Database. Moving it into
the Search Fragment moves that latency to cases where
users are actually searching.

Change-Id: I11368af610ac9e80f9901654f980c2c1e26342a5
Fixes: 34142852
Test: make RunSettingsRoboTests

src/com/android/settings/search2/DatabaseIndexingManager.java

@@ -152,7 +152,7 @@ public class DatabaseIndexingManager {
         return mIsAvailable.get();
     }
 
-    public void update() {
+    public void indexDatabase() {
         AsyncTask.execute(new Runnable() {
             @Override
             public void run() {