Expose RecommendationRequest.Builder as SystemApi.

In order to test our recommender, we need to be able to create
network recommendation requests.

Test: make update-api
Change-Id: I68df0d3e684bcdb90709a34478d2aa669ee23547
diff --git a/api/system-current.txt b/api/system-current.txt
index 4bba111..2480765 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -26175,6 +26175,14 @@
     field public static final android.os.Parcelable.Creator<android.net.RecommendationRequest> CREATOR;
   }
 
+  public static final class RecommendationRequest.Builder {
+    ctor public RecommendationRequest.Builder();
+    method public android.net.RecommendationRequest build();
+    method public android.net.RecommendationRequest.Builder setCurrentRecommendedWifiConfig(android.net.wifi.WifiConfiguration);
+    method public android.net.RecommendationRequest.Builder setNetworkCapabilities(android.net.NetworkCapabilities);
+    method public android.net.RecommendationRequest.Builder setScanResults(android.net.wifi.ScanResult[]);
+  }
+
   public final class RecommendationResult implements android.os.Parcelable {
     method public static android.net.RecommendationResult createConnectRecommendation(android.net.wifi.WifiConfiguration);
     method public static android.net.RecommendationResult createDoNotConnectRecommendation();
diff --git a/core/java/android/net/RecommendationRequest.java b/core/java/android/net/RecommendationRequest.java
index a96f90d..d013f64 100644
--- a/core/java/android/net/RecommendationRequest.java
+++ b/core/java/android/net/RecommendationRequest.java
@@ -41,6 +41,7 @@
      * Builder class for constructing {@link RecommendationRequest} instances.
      * @hide
      */
+    @SystemApi
     public static final class Builder {
         private ScanResult[] mScanResults;
         private WifiConfiguration mCurrentConfig;