Make it possible to hide "most visited" on nnnnnnntp

chrome/browser/resources/new_new_tab.css

 html {
   /* This is needed because of chrome://theme/css/new_tab.css */
   height: 100%;
 }
 
 body {
   margin: 0;
   height: 100%;
   overflow: auto;
   -webkit-user-select: none;
@@ skipping 261 matching lines @@
 
 .section {
   position: fixed;
   font-size: 92%;
 }
 
 html[anim=true][enable-section-animations=true] .section {
   -webkit-transition: top .15s;
 }
 
-.section.disabled {
+.section.disabled,
+#closed-sections-bar .disabled {
   display: none !important;
 }
 
 .section > h2 {
   font-family: Helvetica, Arial, sans-serif;
   font-size: 133%;
   font-weight: normal;
   margin: 0;
   position: relative;
 }
@@ skipping 13 matching lines @@
   left: auto;
   right: -15px;
   -webkit-transform: rotate(180deg);
 }
 
 html[anim=true] .section > h2 > .disclosure {
   -webkit-transition: -webkit-transform .15s;
 }
 
 .section:not(.hidden) > h2 > .disclosure {
-  -webkit-transform:rotate(90deg);
+  -webkit-transform: rotate(90deg);
 }
 
 .section > h2 .back {
   position: absolute;
   left: 0;
   top: 0.56em;
   width: 100%;
   height: 1.5em;
   z-index: 1;
 }
 
 .section > h2 span {
   -webkit-padding-end: 0.30em;
   position: relative;
   z-index: 2;
 }
 
+.section-close-button {
+  -webkit-appearance: none;
+  -webkit-transition: opacity .15s;
+  background-color: transparent;
+  background-image: url(chrome://theme/IDR_CLOSE_BAR);
+  background-position: center center;
+  background-repeat no-repeat;
+  border: 0;
+  height: 21px;
+  margin-top: -10px;
+  position: absolute;
+  right: -21px;
+  top: 50%;
+  width: 21px;
+  opacity: 0;
+  z-index: 3;
+}
+
+html[dir=rtl] .section-close-button {
+  left: -21px;
+  right: auto;
+}
+
+.section > h2:hover .section-close-button,
+.section-close-button:hover {
+ opacity: 1;
+}
+
+.section-close-button:hover {
+  background-image: url(chrome://theme/IDR_CLOSE_BAR_H);
+}
+
+#closed-sections-bar {
+  position: fixed;
+  bottom: 5px;
+}
+
+#closed-sections-bar > button {
+  -webkit-appearance: none;
+  background: none;
+  border: 0;
+  cursor: pointer;
+  font: inherit;
+  margin: 0;
+  margin-right: 1.5em;
+  padding: 0;
+
+  /* Note: The font here should end up the same as .section > h2. A different
+  percentage is needed because the parent element here has a different size. */
+  font-family: Helvetica, Arial, sans-serif;
+  font-size: 122%;
+  font-weight: normal;
+}
+
+#closed-sections-bar > button > img {
+  -webkit-transform: rotate(90deg);
+  position: relative;
+  top: -2px;
+  margin-left: 1px;
+}
+
 .maxiview {
   padding: 5px 0 30px;
   position: absolute;
   -webkit-mask-attachment: fixed;
   opacity: 1;
 }
 
 .maxiview.hiding {
   opacity: 0;
 }
@@ skipping 63 matching lines @@
   }
 }
 
 /* Ensure we have at least 10px horizontal marging. */
 @media (max-width: 712px) {
   #main {
     margin-left: 10px;
     margin-right: 10px;
   }
 }