Import keywords for search engines imported from Firefox

chrome/test/data/firefox_profile/search.json

 {
   "version":7,"buildID":"20140317233623","locale":"en-US","directories":
   {
     "/usr/lib/firefox/distribution/searchplugins/locale/en-US":
     {
       "lastModifiedTime":1398997399000,
       "engines":[
       {
         "_id":"./chrome/test/data/firefox_searchplugins/default/amazondotcom.xml",
         "_name":"Amazon.com",
@@ skipping 54 matching lines @@
       },
       {
         "_id":"./chrome/test/data/firefox_searchplugins/default/yahoo.xml",
         "_name":"Yahoo",
         "_hidden":false,
         "description":"Yahoo Search",
         "__searchForm":"http://search.yahoo.com/",
         "filePath":"[app]/yahoo.xml",
         "_installLocation":3,
         "queryCharset":"UTF-8"
+      },
+      {
+        "_id":"./chrome/test/data/firefox_searchplugins/default/twitter.xml",

[Peter Kasting, 2014/07/31 18:28:21]

Any particular reason to add this?  I'm not seeing a way that it differs from
the entries above and thus would lead to greater test coverage.  Why can't you
just add an alias in search-metadata.json for one of the existing entries,
instead of adding this new one so you can add to it?

[Nikhil, 2014/08/04 12:15:11]

I added new entry in .json files since tests for older versions of Firefox
compared against keywords set in kFirefoxKeywords. I couldn't get all tests to
pass if I changed an existing entry.

But I've now slightly changed the approach based on your suggestion. PTAL.

+        "_name":"Twitter",
+        "_hidden":false,
+        "description":"Realtime Twitter Search",
+        "_searchForm":"https://twitter.com/search/",
+        "filePath":"[app]/twitter.xml",
+        "_installLocation":3,
+        "queryCharset":"UTF-8"
       }]
     },
     "/home/tapughose/.mozilla/firefox/lcd50n4n.default/searchplugins":
     {
       "lastModifiedTime":1399076625000,
       "engines":[
       {
         "_id":"[profile]/webster.xml",
         "_name":"Webster",
         "_hidden":false,
@@ skipping 26 matching lines @@
         "filePath":"[profile]/flickr-tags.xml",
         "_url":"https://addons.mozilla.org/firefox/downloads/latest/4602/addon-4602-latest.xml?src=dp-btn-primary",
         "_installLocation":2,
         "type":3,
         "queryCharset":"UTF-8",
         "_readOnly":false
       }]
     }
   }
 }