Add a hidden method to clear the capabilities of a NetworkRequest

Change-Id: I41d4f2229259d0bf9d68aa00f92f3bf4e2e71fbc

core/java/android/net/NetworkRequest.java

@@ -114,6 +114,18 @@ public class NetworkRequest implements Parcelable {
             return this;
         }
 
+        /**
+         * 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