Make AppBannerInfoBar install WebAPK.

chrome/android/java/strings/android_chrome_strings.grd

Index: chrome/android/java/strings/android_chrome_strings.grd
diff --git a/chrome/android/java/strings/android_chrome_strings.grd b/chrome/android/java/strings/android_chrome_strings.grd
index f35be74eb419fe5ee7d2c89124cc30076b1aba05..f474e01f144e15324e1a948e2809f083bbe0b8c5 100644
--- a/chrome/android/java/strings/android_chrome_strings.grd
+++ b/chrome/android/java/strings/android_chrome_strings.grd
@@ -1526,6 +1526,9 @@ To obtain new licenses, connect to the internet and play your downloaded content
       <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.">
@@ -1588,6 +1591,9 @@ To obtain new licenses, connect to the internet and play your downloaded content
       <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.">