Added feature for surveys provider to Settings

It is now possible to create and show surveys to a user
asking them for feedback within the Settings app.

Test: In Master Branch
Bug: 27823357
Change-Id: I824899045f6ce30e5b6f46d20888da673114f658

src/com/android/settings/overlay/FeatureFactoryImpl.java

@@ -17,15 +17,22 @@
 package com.android.settings.overlay;
 
 import android.content.Context;
+import android.support.annotation.Keep;
 
 /**
  * {@link FeatureFactory} implementation for AOSP Settings.
  */
-public final class FeatureFactoryImpl extends FeatureFactory {
+@Keep
+public class FeatureFactoryImpl extends FeatureFactory {
 
     @Override
     public SupportFeatureProvider getSupportFeatureProvider(Context context) {
         return null;
     }
 
+    @Override
+    public SurveyFeatureProvider getSurveyFeatureProvider(Context context) {
+        return null;
+    }
+
 }