Prevented default backspace handler in File Browser Gallery

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

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /*
  * Base class that Ribbon uses to display photos.
  */
 
 function RibbonClient() {}
 
@@ skipping 557 matching lines @@
     this.cancelFading_();
   } else {
     this.initiateFading_();
   }
 };
 
 Gallery.prototype.onKeyDown_ = function(event) {
   if (this.isEditing_() && this.editor_.onKeyDown(event))
     return;
 
-  switch (event.keyIdentifier) {
+  switch (util.getKeyModifiers(event) + event.keyIdentifier) {
+    case 'U+0008': // Backspace.
+      // The default handler would call history.back and close the Gallery.
+      event.preventDefault();
+      break;
+
     case 'U+001B':  // Escape
       if (this.isEditing_()) {
         this.onEdit_();
       } else if (this.isSharing_()) {
         this.onShare_();
       } else {
         this.onClose_();
       }
       break;
 
@@ skipping 15 matching lines @@
     case 'Left':
       this.ribbon_.selectNext(-1);
       break;
     case 'Right':
       this.ribbon_.selectNext(1);
       break;
     case 'End':
       this.ribbon_.selectLast();
       break;
 
-    case 'U+00DD':
-      if (event.ctrlKey)  // Ctrl+] (cryptic on purpose).
-        this.ribbon_.toggleDebugSlideshow();
+    case 'Ctrl-U+00DD':  // Ctrl+] (cryptic on purpose).
+      this.ribbon_.toggleDebugSlideshow();
       break;
   }
 };
 
 Gallery.prototype.onMouseMove_ = function(e) {
   if (this.clientX_ == e.clientX && this.clientY_ == e.clientY) {
     // The mouse has not moved, must be the cursor change triggered by
     // some of the attributes on the root container. Ignore the event.
     return;
   }
@@ skipping 630 matching lines @@
 ShareMode.prototype.setUp = function() {
   ImageEditor.Mode.prototype.setUp.apply(this, arguments);
   ImageUtil.setAttribute(this.menu_, 'hidden', false);
   ImageUtil.setAttribute(this.button_, 'pressed', false);
 };
 
 ShareMode.prototype.cleanUpUI = function() {
   ImageEditor.Mode.prototype.cleanUpUI.apply(this, arguments);
   ImageUtil.setAttribute(this.menu_, 'hidden', true);
 };