Make AppBannerInfoBar install WebAPK.

chrome/android/java/strings/android_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- android_chrome_strings.grd contains strings for Chrome for Android.
 
 FAQ:
   - How do I add, change, or remove a string?
       Just update this file.
   - Translations will happen automatically??
       Yes, indeed. Just add your string before the branch point and
       make the description good.
@@ skipping 1509 matching lines @@
         Refreshing page
       </message>
 
       <!-- App banner strings -->
       <message name="IDS_APP_BANNER_INSTALLING" desc="Button text indicating that an application is being installed. [CHAR-LIMIT=25]">
         Installing…
       </message>
       <message name="IDS_APP_BANNER_OPEN" desc="Text that indicates that clicking on the button will launch an application. [CHAR-LIMIT=25]">
         Open
       </message>
+      <message name="IDS_APP_BANNER_INSTALLING_WEBAPK" desc="Button text indicating that a WebAPK is being installed. [CHAR-LIMIT=25]">
+        Adding…
+      </message>
 
       <!-- App banner accessibility strings, used for touch exploration -->
       <message name="IDS_APP_BANNER_VIEW_NATIVE_APP_ACCESSIBILITY" desc="Accessibililty text: Describes a prompt promoting the installation of an app related to the current page, including the app's name and its rating.">
         View app <ph name="APP_NAME">%1$s<ex>Gmail</ex></ph> on the Play Store.  Rating: <ph name="APP_RATING">%2$.1f<ex>4.2</ex></ph>.
       </message>
       <message name="IDS_APP_BANNER_VIEW_NATIVE_APP_INSTALL_ACCESSIBILITY" desc="Accessibility text: Indicates that clicking on the button will either purchase the app or install it.">
         Get the app from the Google Play Store: <ph name="APP_ACTION">%s<ex>Install</ex></ph>
       </message>
 
       <message name="IDS_APP_BANNER_VIEW_WEB_APP_ACCESSIBILITY" desc="Accessibililty text: Details the web app being promoted by the current page, including the app name and its URL.">
@@ skipping 42 matching lines @@
         Can’t beam current tab
       </message>
 
       <!-- Add to Home screen strings -->
       <message name="IDS_MENU_ADD_TO_HOMESCREEN" desc="Menu item for adding a shortcut to the Home screen. [CHAR-LIMIT=27]">
         Add to Home screen
       </message>
       <message name="IDS_ADDED_TO_HOMESCREEN" desc="Indicates that the website with the specified name was added to the user's Home screen.">
         <ph name="NAME">%1$s<ex>Google</ex></ph> was added to your Home screen
       </message>
+      <message name="IDS_FAIL_TO_INSTALL_WEBAPK" desc="The installation of a WebAPK fails. [CHAR-LIMIT=27]">
+        Unable to add
+      </message> 
 
       <!-- WebsiteSettingsPopup (PageInfo dialog) -->
       <message name="IDS_PAGE_INFO_SITE_SETTINGS_BUTTON" desc="Text in the button that opens a website's Site Settings from the Page Info dialog.">
         Site Settings
       </message>
       <message name="IDS_PAGE_INFO_PERMISSION_ALLOWED" desc="The label used in the Page Info dialog to describe an allowed permission. Eg: Location - Allowed">
         Allowed
       </message>
       <message name="IDS_PAGE_INFO_PERMISSION_BLOCKED" desc="The label used in the Page Info dialog to describe a blocked permission. Eg: Location - Blocked">
         Blocked
@@ skipping 991 matching lines @@
         Tap this button for quick access to your tabs.
       </message>
 
       <!-- Item Chooser UI strings -->
       <message name="IDS_ITEM_CHOOSER_ITEM_NAME_WITH_ID" desc="To distinguish items with the same name, the item chooser shows the item name with id.">
         <ph name="ITEM_NAME">%1$s<ex>item_name</ex></ph> (<ph name="ITEM_ID">%2$s<ex>item id</ex></ph>)
       </message>
     </messages>
   </release>
 </grit>