Implement <select> Popup Menu using PagePopup

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

 window.jsTestIsAsync = true;
 
 var popupWindow = null;
 
 var popupOpenCallback = null;
 
 function popupOpenCallbackWrapper() {
     popupWindow.removeEventListener("didOpenPicker", popupOpenCallbackWrapper);
     setTimeout(popupOpenCallback, 0);
 }
 
 function waitUntilClosing(callback) {
     setTimeout(callback, 1);
 }
 
 function sendKey(input, keyName, ctrlKey, altKey) {
     var event = document.createEvent('KeyboardEvent');
     event.initKeyboardEvent('keydown', true, true, document.defaultView, keyName, 0, ctrlKey, altKey);
     input.dispatchEvent(event);
 }
 
-function openPicker(input, callback) {
+function openPicker(element, callback) {
     window.moveTo();
-    input.offsetTop; // Force to lay out
-    if (input.type === "color") {
-        input.focus();
-        eventSender.keyDown(" ");
-    } else {
-        sendKey(input, "Down", false, true);
+    element.offsetTop; // Force to lay out
+    if (element.tagName === "SELECT") {
+        sendKey(element, "Down", false, true);
+    } else if (element.tagName === "INPUT") {
+        if (element.type === "color") {
+            element.focus();
+            eventSender.keyDown(" ");
+        } else {
+            sendKey(element, "Down", false, true);
+        }
     }
     popupWindow = window.internals.pagePopupWindow;
     if (typeof callback === "function") {
         popupOpenCallback = (function(callback) {
             // We need to move the window to the top left of available space
             // because the window will move back to (0, 0) when the
             // ShellViewMsg_SetTestConfiguration IPC arrives.
             window.moveTo();
             callback();
         }).bind(this, callback);
         popupWindow.addEventListener("didOpenPicker", popupOpenCallbackWrapper, false);
     }
 }