Move LayoutTests from platform/chromium/... to generic location

LayoutTests/fast/forms/suggestion-picker/resources/suggestion-picker-common.js

 function valueForEntry(element) {
     if (!element)
         return null;
     var value = element.dataset.value;
     if (typeof value === "string")
         return value;
     var action = element.dataset.action;
     if (typeof action === "string")
         return "@" + action;
     return null;
 }
 
 function highlightedEntry() {
     return valueForEntry(popupWindow.document.activeElement);
 }
 
 function entryValues() {
     var elements = popupWindow.document.getElementsByClassName("suggestion-list-entry");
     var values = [];
     for (var i = 0; i < elements.length; ++i)
         values.push(valueForEntry(elements[i]));
     return values;
 }