Add an interface that returns time spent text for app.

Bug: 129266977
Test: robotest
Change-Id: Iaa5b4c5504eccbe0290b1014bd8e25aa3d4c3dd8

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

@@ -81,6 +81,14 @@ public interface ApplicationFeatureProvider {
      */
     Set<String> getKeepEnabledPackages();
 
+    /**
+     * Returns a user readable text explaining how much time user has spent in an app at a
+     * pre-specified duration.
+     */
+    default CharSequence getTimeSpentInApp(String packageName) {
+        return null;
+    }
+
     /**
      * Callback that receives the number of packages installed on the device.
      */