Add recent apps in app & notification

- Introduce a RecentAppsPreferenceControler, which queries
  UsageStatsManager and displays a list of recently used apps.

- Add a control flag for this feature, intially set to false.

- Make ManageApplications a static pref item instead of dynamic one.
  This makes the RecentAppController easier to control "See all"
  preference, which is backed by ManageApplications.

- Also adjust app_items.xml layout to make app item UI consistent with
  preference item.

Change-Id: I0b9e1784faed32b3055ebf96ef98b6a5e422de50
Fix: 33265548
Test: robotests

src/com/android/settings/applications/AppAndNotificationDashboardFragment.java

@@ -16,6 +16,9 @@
 
 package com.android.settings.applications;
 
+import android.app.Activity;
+import android.app.Application;
+import android.app.Fragment;
 import android.content.Context;
 import android.provider.SearchIndexableResource;
 
@@ -56,13 +59,22 @@ public class AppAndNotificationDashboardFragment extends DashboardFragment {
 
     @Override
     protected List<PreferenceController> getPreferenceControllers(Context context) {
-        return buildPreferenceControllers(context);
+        final Activity activity = getActivity();
+        final Application app;
+        if (activity != null) {
+            app = activity.getApplication();
+        } else {
+            app = null;
+        }
+        return buildPreferenceControllers(context, app, this);
     }
 
-    private static List<PreferenceController> buildPreferenceControllers(Context context) {
+    private static List<PreferenceController> buildPreferenceControllers(Context context,
+            Application app, Fragment host) {
         final List<PreferenceController> controllers = new ArrayList<>();
         controllers.add(new SpecialAppAccessPreferenceController(context));
         controllers.add(new AppPermissionsPreferenceController(context));
+        controllers.add(new RecentAppsPreferenceController(context, app, host));
         return controllers;
     }
 
@@ -78,7 +90,7 @@ public class AppAndNotificationDashboardFragment extends DashboardFragment {
 
                 @Override
                 public List<PreferenceController> getPreferenceControllers(Context context) {
-                    return buildPreferenceControllers(context);
+                    return buildPreferenceControllers(context, null, null /* host */);
                 }
             };
 }