Add Home / Launcher apps indexing

- add a BaseSearchIndexProvider to HomeSettings
- use a BroadcastReceiver for tracking add or remove of
Home / Launcher apps
- add "launcher" synonym for "home" too

- also code cleaning for DynamicIndexableContentMonitor

See bug: #16484927 Add "launcher" as a synonym for "home" in settings search

Change-Id: I819f4e5f7bd5e9a7882609206b2733ea1912fc69

src/com/android/settings/search/SearchIndexableResources.java

@@ -118,7 +118,7 @@ public final class SearchIndexableResources {
         sResMap.put(HomeSettings.class.getName(),
                 new SearchIndexableResource(
                         Ranking.getRankForClassName(HomeSettings.class.getName()),
-                        R.xml.home_selection,
+                        NO_DATA_RES_ID,
                         HomeSettings.class.getName(),
                         R.drawable.ic_settings_home));