Photo Editor brightness tool fix.

chrome/browser/resources/file_manager/js/image_editor/image_editor.js

Index: chrome/browser/resources/file_manager/js/image_editor/image_editor.js
diff --git a/chrome/browser/resources/file_manager/js/image_editor/image_editor.js b/chrome/browser/resources/file_manager/js/image_editor/image_editor.js
index e8a79797fc59f08f0679852c42fc103ec2281307..ce24d93234c2e0ab1571a8c5e5e28413dda4c6f7 100644
--- a/chrome/browser/resources/file_manager/js/image_editor/image_editor.js
+++ b/chrome/browser/resources/file_manager/js/image_editor/image_editor.js
@@ -367,8 +367,11 @@ ImageEditor.prototype.leaveMode = function(commit) {
   this.currentMode_.cleanUpUI();
   if (commit) {
     var self = this;
-    this.commandQueue_.execute(this.currentMode_.getCommand());
-    this.updateUndoRedo();
+    var command = this.currentMode_.getCommand();
+    if (command) {  // Could be null if the user did not do anything.
+      this.commandQueue_.execute(command);
+      this.updateUndoRedo();
+    }
   }
   this.currentMode_.cleanUpCaches();
   this.currentMode_ = null;