Prevented default backspace handler in File Browser Gallery

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 6115a36489a84d9ce3928015c7c15d099b1da078..37701311020fd06c0d53cbf85d19253cbd27520b 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
@@ -414,7 +414,7 @@ ImageEditor.prototype.leaveModeGently = function() {
 };
 
 ImageEditor.prototype.onKeyDown = function(event) {
-  switch(event.keyIdentifier) {
+  switch(util.getKeyModifiers(event) + event.keyIdentifier) {
     case 'U+001B': // Escape
     case 'Enter':
       if (this.getMode()) {
@@ -423,19 +423,17 @@ ImageEditor.prototype.onKeyDown = function(event) {
       }
       break;
 
-    case 'U+005A':  // 'z'
-      if (event.ctrlKey) {
-        if (event.shiftKey) {
-          if (this.commandQueue_.canRedo()) {
-            this.redo();
-            return true;
-          }
-        } else {
-          if (this.commandQueue_.canUndo()) {
-            this.undo();
-            return true;
-          }
-        }
+    case 'Ctrl-U+005A':  // Ctrl+Z
+      if (this.commandQueue_.canUndo()) {
+        this.undo();
+        return true;
+      }
+      break;
+
+    case 'Ctrl-Shift-U+005A':  // Ctrl+Shift-Z
+      if (this.commandQueue_.canRedo()) {
+        this.redo();
+        return true;
       }
       break;
   }