Make the Most Visited tile focus state more apparent to match the online NTP.

chrome/browser/resources/local_ntp/local_ntp.css

Index: chrome/browser/resources/local_ntp/local_ntp.css
diff --git a/chrome/browser/resources/local_ntp/local_ntp.css b/chrome/browser/resources/local_ntp/local_ntp.css
index 40daad8be323d95a6b417357d6a4ccf8a482dccd..d12f6e7e261dc45fc5eaa570215866d854285afd 100644
--- a/chrome/browser/resources/local_ntp/local_ntp.css
+++ b/chrome/browser/resources/local_ntp/local_ntp.css
@@ -242,7 +242,8 @@ body.fakebox-focused #cursor {
   border-color: #7f7f7f
 }
 
-.mv-thumb {
+.mv-thumb,
+.mv-mask {
   border: none;
   cursor: pointer;
   height: 83px;
@@ -261,6 +262,17 @@ body.fakebox-focused #cursor {
   width: 140px;
 }
 
+.mv-mask {
+  opacity: 0.35;
+}
+
+.mv-page:focus .mv-mask {
+  -webkit-transition: background-color 100ms ease-in-out;
+  background: -webkit-linear-gradient(rgba(255, 255, 255, 0),
+    rgba(255, 255, 255, 0) 80%, rgba(255, 255, 255, 0.9));
+  background-color: black;
+}
+
 .mv-x-hide .mv-x {
   display: none;
 }