Remove the BackspaceGoesBack flag.

chrome/browser/resources/chromeos/keyboard_overlay_data.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.
 
 // This is a generated file but may contain local modifications. See
 // src/tools/gen_keyboard_overlay_data/gen_keyboard_overlay_data.py --help
 
 var keyboardOverlayData = {
   'inputMethodIdToOverlayId': {
     'xkb:be::fra': 'fr',
@@ skipping 15793 matching lines @@
     '=<>SEARCH': 'keyboardOverlayF12',
     'ALT<>SEARCH': 'keyboardOverlayToggleCapsLock',
     '[<>ALT': 'keyboardOverlayDockWindowLeft',
     ']<>ALT': 'keyboardOverlayDockWindowRight',
     'a<>CTRL': 'keyboardOverlaySelectAll',
     'arrowkeys<>CTRL': 'keyboardOverlayWordMove',
     'b<>ALT<>SHIFT': 'keyboardOverlayFocusBookmarks',
     'b<>CTRL<>SHIFT': 'keyboardOverlayToggleBookmarkBar',
     'back<>CTRL': 'keyboardOverlayFocusPreviousPane',
     'back<>SEARCH': 'keyboardOverlayF1',
-    'backspace': 'keyboardOverlayGoBack',
     'backspace<>ALT': 'keyboardOverlayDelete',
     'backspace<>CTRL': 'keyboardOverlayDeleteWord',
     'backspace<>CTRL<>SHIFT': 'keyboardOverlayClearBrowsingDataDialog',
     'backspace<>SEARCH': 'keyboardOverlayDelete',
-    'backspace<>SHIFT': 'keyboardOverlayGoForward',
     'bright down<>ALT': 'keyboardOverlayDecreaseKeyBrightness',
     'bright down<>ALT<>CTRL': 'keyboardOverlayMagnifierDecreaseZoom',
     'bright down<>SEARCH': 'keyboardOverlayF6',
     'bright up<>ALT': 'keyboardOverlayIncreaseKeyBrightness',
     'bright up<>ALT<>CTRL': 'keyboardOverlayMagnifierIncreaseZoom',
     'bright up<>SEARCH': 'keyboardOverlayF7',
     'c<>CTRL': 'keyboardOverlayCopy',
     'c<>CTRL<>SHIFT': 'keyboardOverlayDomInspector',
     'd<>ALT': 'keyboardOverlayFocusAddressBar',
     'd<>CTRL': 'keyboardOverlayBookmarkCurrentPage',
@@ skipping 106 matching lines @@
     'vol. down<>SEARCH': 'keyboardOverlayF9',
     'vol. up<>SEARCH': 'keyboardOverlayF10',
     'vol. up<>SEARCH<>SHIFT': 'keyboardOverlayContextMenu',
     'w<>CTRL': 'keyboardOverlayCloseTab',
     'w<>CTRL<>SHIFT': 'keyboardOverlayCloseWindow',
     'x<>CTRL': 'keyboardOverlayCut',
     'z<>ALT<>CTRL': 'keyboardOverlayToggleChromevoxSpokenFeedback',
     'z<>CTRL': 'keyboardOverlayUndo'
   }
 };