Fix a Closure Compiler error.

ui/file_manager/gallery/js/image_editor/image_resize.js

Index: ui/file_manager/gallery/js/image_editor/image_resize.js
diff --git a/ui/file_manager/gallery/js/image_editor/image_resize.js b/ui/file_manager/gallery/js/image_editor/image_resize.js
index 9c186c35d2ecefb4d6d234238cb81937feb8f622..3cfaa35aca94142352b4e53e6baafe4f661bd6ef 100644
--- a/ui/file_manager/gallery/js/image_editor/image_resize.js
+++ b/ui/file_manager/gallery/js/image_editor/image_resize.js
@@ -36,6 +36,9 @@ ImageEditor.Mode.Resize = function() {
   /** @private {HTMLElement} */
   this.heightInputElement_ = null;
 
+  /** @private {HTMLElement} */
+  this.lockIcon_ = null;
+
   /** @private {number} */
   this.ratio_ = 0;