Move event handler to its own file.

Change-Id: If9e14ec381bfb09f5d57a405956612fb17c3ac1b
diff --git a/src/com/android/documentsui/dirlist/ActionModeController.java b/src/com/android/documentsui/dirlist/ActionModeController.java
index 8038768..6ef793c 100644
--- a/src/com/android/documentsui/dirlist/ActionModeController.java
+++ b/src/com/android/documentsui/dirlist/ActionModeController.java
@@ -33,8 +33,8 @@
 import com.android.documentsui.MenuManager;
 import com.android.documentsui.Menus;
 import com.android.documentsui.R;
-import com.android.documentsui.base.FunctionalInterfaces.EventHandler;
 import com.android.documentsui.Shared;
+import com.android.documentsui.base.EventHandler;
 import com.android.documentsui.dirlist.MultiSelectManager.Selection;
 
 import java.util.function.Consumer;