Zen: Make condition providers available via @SystemApi.

Bug:16819503
Change-Id: Ibd7004f7a0928d3f14f9ccd55088cf645d5285e2

core/java/android/service/notification/ConditionProviderService.java

@@ -17,6 +17,7 @@
 package android.service.notification;
 
 import android.annotation.SdkConstant;
+import android.annotation.SystemApi;
 import android.app.INotificationManager;
 import android.app.Service;
 import android.content.Context;
@@ -44,6 +45,7 @@ import android.util.Log;
  *
  * @hide
  */
+@SystemApi
 public abstract class ConditionProviderService extends Service {
     private final String TAG = ConditionProviderService.class.getSimpleName()
             + "[" + getClass().getSimpleName() + "]";

core/res/AndroidManifest.xml

@@ -2773,7 +2773,7 @@
         android:description="@string/permdesc_bindNotificationListenerService"
         android:protectionLevel="signature" />
 
-    <!-- Must be required by an {@link
+    <!-- @SystemApi Must be required by a {@link
          android.service.notification.ConditionProviderService},
          to ensure that only the system can bind to it.
          @hide -->