[Icons NTP] Make Local NTP render largeIconUrl instead of thumbnail, if available.

chrome/browser/resources/local_ntp/most_visited_thumbnail.css

Index: chrome/browser/resources/local_ntp/most_visited_thumbnail.css
diff --git a/chrome/browser/resources/local_ntp/most_visited_thumbnail.css b/chrome/browser/resources/local_ntp/most_visited_thumbnail.css
index 52eb41597910e2ac1fc08a4c7e8c5a7170c14143..ec4a704c36e08a2587b61c4de950a8d68641ef9d 100644
--- a/chrome/browser/resources/local_ntp/most_visited_thumbnail.css
+++ b/chrome/browser/resources/local_ntp/most_visited_thumbnail.css
@@ -35,8 +35,20 @@ span.blocker {
   width: 100%;
 }
 
-img {
+img.thumbnail {
   height: auto;
   min-height: 100%;
   width: 100%;
 }
+
+img.large-icon {
+  height: 48px;
+  left: 50%;
+  margin-left: -24px;
+  margin-top: -24px;
+  min-height: initial;
+  position: absolute;
+  top: 50%;
+  vertical-align: middle;
+  width: 48px;
+}