Add a hidden method to clear the capabilities of a NetworkRequest

Change-Id: I41d4f2229259d0bf9d68aa00f92f3bf4e2e71fbc
diff --git a/core/java/android/net/NetworkRequest.java b/core/java/android/net/NetworkRequest.java
index 7838b47..e61594c 100644
--- a/core/java/android/net/NetworkRequest.java
+++ b/core/java/android/net/NetworkRequest.java
@@ -115,6 +115,18 @@
         }
 
         /**
+         * Completely clears all the {@code NetworkCapabilities} from this builder instance,
+         * removing even the capabilities that are set by default when the object is constructed.
+         *
+         * @return The builder to facilitate chaining.
+         * @hide
+         */
+        public Builder clearCapabilities() {
+            mNetworkCapabilities.clearAll();
+            return this;
+        }
+
+        /**
          * Adds the given transport requirement to this builder.  These represent
          * the set of allowed transports for the request.  Only networks using one
          * of these transports will satisfy the request.  If no particular transports