DOMUI Prefs: Implement inline editability for startup pages

chrome/browser/resources/options/search_engine_manager.css

 #searchEngineList {
   -webkit-border-radius: 2px;
   border-bottom: 1px solid #d9d9d9;
   height: auto;
 }
 
 #searchEngineManagerPage .left-side-table {
   margin-top: 12px;
 }
 
@@ skipping 63 matching lines @@
 
 #searchEngineList .name-column :last-child {
   -webkit-box-flex: 1;
 }
 
 #searchEngineList input {
   box-sizing: border-box;
   margin: 0;
   width: 100%;
 }
-
-#searchEngineList .static-text {
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-#searchEngineList > :not([editing]) [editmode=true] {
-  display: none;
-}
-
-#searchEngineList > [editing] [editmode=false] {
-  display: none;
-}
-
-#searchEngineList input.invalid {
-  /* TODO(stuartmorgan): Replace with actual badging */
-  background-color: pink;
-}