Adds an experiment that enabled SuggestionsService suggestions (MostLikely) on LocalNTP

chrome/browser/resources/local_ntp/most_visited_single.js

Index: chrome/browser/resources/local_ntp/most_visited_single.js
diff --git a/chrome/browser/resources/local_ntp/most_visited_single.js b/chrome/browser/resources/local_ntp/most_visited_single.js
index 0e55a5a932f7cf713e547f9e88c9d9c2865c9547..c41d35c7afafa8c4be01f5b623cde32572ae1a8c 100644
--- a/chrome/browser/resources/local_ntp/most_visited_single.js
+++ b/chrome/browser/resources/local_ntp/most_visited_single.js
@@ -277,9 +277,13 @@ var addTile = function(args) {
   if (args.rid) {
     var data = chrome.embeddedSearch.searchBox.getMostVisitedItemData(args.rid);
     data.tid = data.rid;
-    data.thumbnailUrls = [data.thumbnailUrl];
-    data.faviconUrl = 'chrome-search://favicon/size/16@' +
-        window.devicePixelRatio + 'x/' + data.renderViewId + '/' + data.tid;
+    if (data.thumbnailUrl) {
+      data.thumbnailUrls = [data.thumbnailUrl];

[Mathieu, 2015/07/28 13:32:42]

should we make sure data.thumbnailUrls is not undefined when exiting addTile? I
know in your proposed change it wouldn't, but later on that may change.
renderTile wouldn't handle it well.

[fserb, 2015/07/28 17:55:29]

Done.

+    }
+    if (!data.faviconUrl) {
+      data.faviconUrl = 'chrome-search://favicon/size/16@' +
+          window.devicePixelRatio + 'x/' + data.renderViewId + '/' + data.tid;
+    }
     tiles.appendChild(renderTile(data));
     logEvent(LOG_TYPE.NTP_CLIENT_SIDE_SUGGESTION);
   } else if (args.id) {