DOMUI Prefs: Fix the way recent page rows are sized and truncated.

chrome/browser/resources/options/add_startup_page_overlay.css

 #addStartupPageOverlay {
   width: 500px;
 }
 
 #addURLBlock {
   display: -webkit-box;
   margin: 1ex 0 2ex 0;
 }
 
 #addURLBlock > * {
   display: block;
 }
 
 #addURLBlock > span {
   padding-top: 4px;
 }
 
 #addStartupPageURL {
   -webkit-box-flex: 1;
 }
 
 #addStartupRecentPageList {
   height: 320px;
 }
 
+#addStartupRecentPageList .vertical-center {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  width: 100%;
+  white-space: nowrap;
+  color: hsl(0, 0%, 70%);
+}
+
+#addStartupRecentPageList .title {
+  box-sizing: border-box;
+  color: black;
+  display: inline-block;
+  max-width: 100%;
+}
+
 #addStartupRecentPageList .url {
-  display: none;
-  color: hsl(0, 0%, 70%);
   -webkit-padding-start: 3ex;
 }
 
-#addStartupRecentPageList > :hover > .url,
-#addStartupRecentPageList > [selected] > .url {
-  display: inline;
+#addStartupRecentPageList > :not(:hover):not([selected]) > .url,
+  display: none;
 }
 
 #addStartupPageOverlay .action-area {
   margin-top: 2ex;
 }