WebUI Prefs: Don't use display:block for labels

chrome/browser/resources/options/browser_options_page.css

 #startupPageManagement.settings-list > :last-child {
   border-top: 1px solid #d9d9d9;
   padding: 5px 10px;
 }
 
 #startupPagesList {
   min-height: 64px;
 }
 
 #startupPagesList .title {
   width: 40%;
 }
 
 #startupPagesList .url {
   -webkit-box-flex: 1;
   color: #666;
 }
 
 #customHomePageGroup {
   display: -webkit-box;
   -webkit-box-orient: horizontal;
 }
 
-#customHomePageGroup > div {
+#customHomePageGroup > :last-child {
   -webkit-padding-start: 1ex;
   -webkit-box-flex: 1;
 }
 
 #homepageURL {
   box-sizing: border-box;
   padding-top: 3px;
   width: 100%;
 }
 
@@ skipping 29 matching lines @@
 #instantConfirmText {
   font-family: inherit;
   white-space: pre-wrap;
   width: 500px;
 }
 
 #instantConfirmLearnMore {
   position: absolute;
   bottom: 18px;
 }