Re-add backspace-goes-back as a default disabled finch trial

chrome/browser/app_mode/app_mode_utils.cc

 // Copyright (c) 2013 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.
 
 #include "chrome/browser/app_mode/app_mode_utils.h"
 
 #include <stddef.h>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/common/chrome_switches.h"
 
 namespace chrome {
 
 bool IsCommandAllowedInAppMode(int command_id) {
   DCHECK(IsRunningInForcedAppMode());
 
   const int kAllowed[] = {
       IDC_BACK,
       IDC_FORWARD,
+      IDC_BACKSPACE_BACK,
+      IDC_BACKSPACE_FORWARD,
       IDC_RELOAD,
       IDC_STOP,
       IDC_RELOAD_BYPASSING_CACHE,
       IDC_RELOAD_CLEARING_CACHE,
       IDC_CUT,
       IDC_COPY,
       IDC_PASTE,
       IDC_ZOOM_PLUS,
       IDC_ZOOM_NORMAL,
       IDC_ZOOM_MINUS,
@@ skipping 13 matching lines @@
       IsRunningInForcedAppMode();
 }
 
 bool IsRunningInForcedAppMode() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   return command_line->HasSwitch(switches::kForceAppMode) &&
       command_line->HasSwitch(switches::kAppId);
 }
 
 }  // namespace chrome