[Android]: Hide add-to-homescreen app menu item when WebAPK is installed

chrome/android/java/res/menu/main_menu.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 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. -->
 
 <menu xmlns:android="http://schemas.android.com/apk/res/android">
     <!-- These menu items are common to tablet and phone. -->
     <group android:id="@+id/PAGE_MENU"
         android:visible="false">
         <item android:id="@+id/icon_row_menu_id"
@@ skipping 39 matching lines @@
               <item android:id="@+id/share_menu_id"
                 android:title="@string/menu_share_page"/>
               <item android:id="@+id/direct_share_menu_id"
                 android:title="@null" />
           </menu>
         </item>
         <item android:id="@+id/find_in_page_id"
             android:title="@string/menu_find_in_page" />
         <item android:id="@+id/add_to_homescreen_id"
             android:title="@string/menu_add_to_homescreen" />
+        <item android:id="@+id/open_webapk_id"
+            android:title="@string/menu_open_webapk" />
         <item android:id="@+id/request_desktop_site_id"
             android:title="@string/menu_request_desktop_site"
             android:checkable="true"
             android:icon="?android:attr/listChoiceIndicatorMultiple" />
         <item android:id="@+id/reader_mode_prefs_id"
             android:title="@string/menu_reader_mode_prefs"
             android:icon="@drawable/reader_mode_prefs_icon" />
         <item android:id="@+id/preferences_id"
             android:title="@string/menu_preferences" />
         <item android:id="@+id/help_id"
@@ skipping 23 matching lines @@
     <group android:id="@+id/TABLET_EMPTY_MODE_MENU"
         android:visible="false">
         <item android:id="@id/new_tab_menu_id"
             android:title="@string/menu_new_tab" />
         <item android:id="@id/new_incognito_tab_menu_id"
             android:title="@string/menu_new_incognito_tab" />
         <item android:id="@id/preferences_id"
             android:title="@string/menu_preferences" />
     </group>
 </menu>
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