Remove unused import.

Change-Id: I0d6a6e15b90f3fd3c94a739e7998e722165ec597
diff --git a/src/main/java/com/android/tools/r8/D8.java b/src/main/java/com/android/tools/r8/D8.java
index 3a33053..327d206 100644
--- a/src/main/java/com/android/tools/r8/D8.java
+++ b/src/main/java/com/android/tools/r8/D8.java
@@ -28,7 +28,6 @@
 import java.io.OutputStreamWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;