Remove the BaseColumns inheritance

This is done so that it doesn't bleed into a public API

Bug: 2245521

Change-Id: I2e5f728553f074f0dc2e8a3dfdf90b1c1f189bad
diff --git a/core/java/android/provider/Downloads.java b/core/java/android/provider/Downloads.java
index a93cee7..3774156 100644
--- a/core/java/android/provider/Downloads.java
+++ b/core/java/android/provider/Downloads.java
@@ -27,7 +27,7 @@
  */
 // For 1.0 the download manager can't deal with abuse from untrusted apps, so
 // this API is hidden.
-public final class Downloads implements BaseColumns {
+public final class Downloads {
     private Downloads() {}
 
     /**