NTP: Use the store as the last thumbnail in case we have no apps installed....

chrome/browser/resources/ntp/apps.css

 /* Apps */
 
 #apps-section .app,
 #apps-section .app[new=installed] {
   -webkit-box-sizing: border-box;
   -webkit-perspective: 400;
   border-radius: 10px;
   color: black;
   display: inline-block;
   margin: 5px 3px;
@@ skipping 103 matching lines @@
 
 #apps-section .app[new=new] {
   opacity: 0;
 }
 
 #apps-section .app[new=installed] {
   -webkit-animation: bounce .5s ease-in-out;
   -webkit-transition: opacity .5s;
 }
 
+#web-store-entry {
+  background-image: url("web_store_icon.png");
+}
+
 /* Make items on the wrong side non focusable by hiding them. */
 .app:not(.config) > .back button,
 .app.config > .front button,
 .app.config > .front a {
   display: none;
 }
 
 html[has_3d=true] .app.config > .front {
   -webkit-transform: rotateY(180deg);
 }
@@ skipping 10 matching lines @@
   display: none;
 }
 
 html[has_3d=false] .app > .back {
   display: none;
 }
 
 html[has_3d=false] .app.config > .back {
   display: block;
 }