Revert "Revert "Unhide RouteInfo#getType and related fields""

This reverts commit 6d1ea2bb16451e43b5a2c3da30b49ecfc40037cc.

Reason for revert: Re-landing changes not related to postsubmit failure

Change-Id: If7940801518be5ddec91270b3663ddfc8b42eadb
diff --git a/framework/src/android/net/RouteInfo.java b/framework/src/android/net/RouteInfo.java
index fad3144..df5f151 100644
--- a/framework/src/android/net/RouteInfo.java
+++ b/framework/src/android/net/RouteInfo.java
@@ -86,16 +86,26 @@
     private final String mInterface;
 
 
-    /** Unicast route. @hide */
-    @SystemApi
+    /**
+     * Unicast route.
+     *
+     * Indicates that destination is reachable directly or via gateway.
+     **/
     public static final int RTN_UNICAST = 1;
 
-    /** Unreachable route. @hide */
-    @SystemApi
+    /**
+     * Unreachable route.
+     *
+     * Indicates that destination is unreachable.
+     **/
     public static final int RTN_UNREACHABLE = 7;
 
-    /** Throw route. @hide */
-    @SystemApi
+    /**
+     * Throw route.
+     *
+     * Indicates that routing information about this destination is not in this table.
+     * Routing lookup should continue in another table.
+     **/
     public static final int RTN_THROW = 9;
 
     /**
@@ -391,10 +401,7 @@
      * Retrieves the type of this route.
      *
      * @return The type of this route; one of the {@code RTN_xxx} constants defined in this class.
-     *
-     * @hide
      */
-    @SystemApi
     @RouteType
     public int getType() {
         return mType;