Remove unused import in Enqueuer.

Change-Id: I3d4809d4d17ccf65d0720cb09e7fbcd364001e45
diff --git a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
index dba8d9c..98559ad 100644
--- a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
+++ b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
@@ -51,7 +51,6 @@
 import com.android.tools.r8.graph.DexType;
 import com.android.tools.r8.graph.DirectMappedDexApplication;
 import com.android.tools.r8.graph.DirectMappedDexApplication.Builder;
-import com.android.tools.r8.graph.FieldAccessInfoCollection;
 import com.android.tools.r8.graph.FieldAccessInfoCollectionImpl;
 import com.android.tools.r8.graph.FieldAccessInfoImpl;
 import com.android.tools.r8.graph.InnerClassAttribute;