Add history popup when long pressing on the back key.

chrome/android/java/res/values/strings.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- 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.
 -->
 
 <resources xmlns:android="http://schemas.android.com/apk/res/android" xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
     <!-- Popup button for user to confirm a beforeunload dialog box triggered by a page navigation,
          i.e. they want to leave the current page [CHAR-LIMIT=20] -->
     <string name="leave_this_page">Leave this Page</string>
     <!-- Popup button for user to cancel a beforeunload dialog box triggerd by a page navigation,
          i.e. they want to stay on the current page [CHAR-LIMIT=20] -->
     <string name="stay_on_this_page">Stay on this Page</string>
     <!-- Popup button for user to confirm a beforeunload dialog box triggered by a page reload
          action, i.e. they want to reload the current page [CHAR-LIMIT=20] -->
     <string name="reload_this_page">Reload this Page</string>
     <!-- Popup button for user to cancel a beforeunload dialog box triggered by a page reload
          action, i.e. they do not want to reload the current page [CHAR-LIMIT=20] -->
     <string name="dont_reload_this_page">Don\'t reload</string>
 
+    <!-- Label for the list item that opens the full navigation history.  [CHAR-LIMIT=32] -->
+    <string name="show_history_label">Show full history</string>
+
     <!-- JS modal dialogs -->
     <!-- Standard popup button for allowing user confirmation of some webpage
          event. [CHAR-LIMIT=12] -->
     <string name="js_modal_dialog_confirm">OK</string>
     <!-- Standard popup button for allowing user to cancel some webpage event.
          [CHAR-LIMIT=12] -->
     <string name="js_modal_dialog_cancel">Cancel</string>
     <!-- Checkbox allowing users to forgoe an additional prompts from a web
          page. [CHAR-LIMIT=None] -->
     <string name="suppress_js_modal_dialogs">Prevent this page from creating additional dialogs</string>
     <!-- Content description for the input javascript modal dialog prompt. [CHAR-LIMIT=32] -->
     <string name="accessibility_js_modal_dialog_prompt">Prompt</string>
 </resources>