Local NTP, Fakebox: fix magnifying glass size regression

This happened by accident in r709236 when polishing realbox icon sizes.

R=dpapad@chromium.org

Fixed: 1018095
Bug: 1017495
Change-Id: I23345b12d14e400eb014c0a6b25b88708e4a631f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881483
Commit-Queue: Dan Beam <dbeam@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Auto-Submit: Dan Beam <dbeam@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709739}

chrome/browser/resources/local_ntp/local_ntp.css

@@ -356,6 +356,10 @@ html[dir=rtl] #fakebox > input {
   right: 0;
 }
 
+#fakebox .search-icon {
+  -webkit-mask-size: 20px;
+}
+
 #fakebox-text {
   bottom: 0;
   color: rgb(117, 117, 117);