[NTP] Fix 1px jitter in custom link tiles

Temporary fix for the 1px jitter that occurs when a custom link is
hovered. Will be removed once the Blink library is fixed.

Also fix a missing parentheses.

Bug: 897006
Change-Id: Idea7a921d1933845fb3ab00ecaf649161b21b114
Reviewed-on: https://chromium-review.googlesource.com/c/1295170Reviewed-by: Ramya Nagarajan <ramyan@chromium.org>
Commit-Queue: Kristi Park <kristipark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602192}

chrome/browser/resources/local_ntp/local_ntp.css

@@ -675,7 +675,10 @@ html[dir=rtl] #attribution,
 }
 
 #mv-single {
-  border: none;
+  /* Quick fix for 1px jitter that occurs when border is set to none or 0 (see
+   * https://crbug.com/897006).
+   * TODO(kristipark): Revert once this is fixed in the Blink library. */
+  border: 1px solid transparent;
   height: 100%;
   width: 100%;
 }

chrome/browser/resources/local_ntp/most_visited_single.js

@@ -437,8 +437,8 @@ var swapInNewTiles = function() {
         parent.lastChild.querySelectorAll('.' + CLASSES.MD_TITLE));
 
     if (cur.childNodes.length > MD_MAX_TILES_PER_ROW) {
-      cur.style.maxWidth =
-          'calc(var(--md-tile-width) * ' + Math.ceil(cur.childNodes.length / 2);
+      cur.style.maxWidth = 'calc(var(--md-tile-width) * ' +
+          Math.ceil(cur.childNodes.length / 2) + ')';
     }
 
     // Prevent keyboard navigation to tiles that are not visible.