[Android] Allow setting recently visited search engines as default search engine

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 239 matching lines @@
       <!-- Search engine preferences -->
       <message name="IDS_PREFS_SEARCH_ENGINE" desc="Title for Search Engine preferences. [CHAR-LIMIT=32]">
         Search engine
       </message>
       <message name="IDS_SEARCH_ENGINE_LOCATION_ALLOWED" desc="The text of a link displayed when location permission for a particular search engine is allowed.">
         Location is allowed
       </message>
       <message name="IDS_SEARCH_ENGINE_LOCATION_BLOCKED" desc="The text of a link displayed when location permission for a particular search engine is blocked.">
         Location is blocked
       </message>
+      <message name="IDS_SEARCH_ENGINE_RECENTLY_VISITED" desc="Divider between prepopulated and recently visited search engines.">

[gone, 2016/11/28 21:37:02]

Maybe desc -> "Header for the list of recently visited search engines"?  Divider
doesn't say much.

[ltian, 2016/11/29 02:44:02]

Done.

+        Recently visited
+      </message>
 
       <!-- Autofill preferences -->
       <message name="IDS_PREFS_AUTOFILL" desc="Title for 'Autofill forms' settings, which control what personal data can be automatically filled into web page forms. [CHAR-LIMIT=32]">
         Autofill forms
       </message>
       <message name="IDS_AUTOFILL_PROFILES_TITLE" desc="Header above the list of profiles (which contain the user's name, address, etc) that can be automatically filled into web page forms. [CHAR-LIMIT=32]">
         Addresses
       </message>
       <message name="IDS_AUTOFILL_CREDIT_CARDS_TITLE" desc="Header above the list of the user's credit cards that can be automatically filled into web page forms. [CHAR-LIMIT=32]">
         Credit cards
@@ skipping 2482 matching lines @@
       <message name="IDS_WEBAPK_UNKNOWN_SOURCES_DIALOG_MESSAGE" desc="Text of dialog warning user that installation from Unknown sources is required for WebAPK experiment">
         Turn on “Unknown sources” in Android security settings to try "Improved Add to Home screen" experiment. Be sure to disable this setting when you’re done trying it out.
       </message>
 
       <message name="IDS_WEBAPK_UNKNOWN_SOURCES_SETTINGS_BUTTON" desc="Button label for opening Android Settings from dialog warning user that installation from Unknown sources is required for WebAPK experiment.">
         Settings
       </message>
     </messages>
   </release>
 </grit>