[NTP] The ntp-ui-md flag should not enable MD icons for Most Visited

Setting ntp-ui-md also enables Material Design for Most Visited. This
should not be the case.

Cq-Include-Trybots: luci.chromium.try:closure_compilation
Change-Id: Ic44b16b7016b7c8a5d807e81ce7b623227a57c72
Reviewed-on: https://chromium-review.googlesource.com/1137258
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575282}

chrome/browser/resources/local_ntp/local_ntp.js

@@ -949,7 +949,7 @@ function init() {
   args.push('removeTooltip=' +
       encodeURIComponent(configData.translatedStrings.removeThumbnailTooltip));
 
-  if (configData.isMDIconsEnabled || configData.isMDUIEnabled) {
+  if (configData.isMDIconsEnabled) {
     args.push('enableMD=1');
   }