Implement IsReadyToPay handling

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 2570 matching lines @@
       </message>
       <message name="IDS_PAYMENTS_SELECT_SHIPPING_ADDRESS_FOR_SHIPPING_METHODS" desc="Text implying that a user needs to pick a shipping address to see the shipping methods.">
         Select a shipping address to check shipping methods and requirements.
       </message>
       <message name="IDS_PAYMENTS_CHECKING_OPTION" desc="Text explaining that the option the user selected is being checked and verified.">
         Checking
       </message>
       <message name="IDS_PAYMENTS_UNSUPPORTED_SHIPPING_ADDRESS" desc="Text implying that a user needs to pick a different shipping address, because the currently selected address is not supported.">
         Unsupported shipping address. Select a different adddress.
       </message>
+      <message name="IDS_PAYMENTS_ANDROID_APP_ERROR" desc="Error message that is shown when an Android payment application fails to start.">
+        Unable to launch payment app
+      </message>
 
       <!-- Migration strings -->
       <message name="IDS_TAB_SWITCHER_CALLOUT_HEADER" desc="Header for the Tab Switcher callout.">
         Quickly switch tabs
       </message>
       <message name="IDS_TAB_SWITCHER_CALLOUT_BODY" desc="Indicates that clicking the tab switcher button gives you quick access to your tabs.">
         Tap this button for quick access to your tabs.
       </message>
 
       <!-- Special locale UI strings -->
@@ skipping 17 matching lines @@
       <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>
 
       <message name="IDS_INSTANT_APPS_OPEN_IN_APP" desc="Button label for the user action that will open an Instant App.">
         Open app
       </message>
     </messages>
   </release>
 </grit>