Make DocsUI only log to device policy logger on R+

Make DocsUI's version of DevicePolicyEventLogger#write a no-op pre-R.

Fixes: 150904641
Test: atest DocumentsUIGoogleTests:com.android.documentsui.dirlist.MessageTest
Change-Id: If790247e54a070dcbd09908ecb4a6228d0bdfafe
diff --git a/src/com/android/documentsui/Metrics.java b/src/com/android/documentsui/Metrics.java
index 90f2b6f..9221ec9 100644
--- a/src/com/android/documentsui/Metrics.java
+++ b/src/com/android/documentsui/Metrics.java
@@ -45,6 +45,7 @@
 import com.android.documentsui.roots.ProvidersAccess;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperationService.OpType;
+import com.android.documentsui.util.VersionUtils;
 
 import java.io.FileNotFoundException;
 import java.util.List;
@@ -637,11 +638,15 @@
     }
 
     /**
-     * The implementation is copied from StatsLogInternal for the DEVICE_POLICY_EVENT.
+     * The implementation is copied from StatsLogInternal for the DEVICE_POLICY_EVENT. This is a
+     * no-op pre-R.
      */
     private static class DevicePolicyEventLogger {
         public static void write(@DevicePolicyMetricConsts.EventId int eventId,
                 boolean booleanValue) {
+            if (!VersionUtils.isAtLeastR()) {
+                return;
+            }
             final StatsEvent.Builder builder = StatsEvent.newBuilder();
             builder.setAtomId(DevicePolicyMetricConsts.ATOM_DEVICE_POLICY_EVENT);
             builder.writeInt(eventId); // eventId