[Files.app] Add a test to check tabfocus

ui/file_manager/file_manager/background/js/test_util_base.js

Index: ui/file_manager/file_manager/background/js/test_util_base.js
diff --git a/ui/file_manager/file_manager/background/js/test_util_base.js b/ui/file_manager/file_manager/background/js/test_util_base.js
index b115687d2b2b905affc21ab0a151bb591b12a883..4e0e8c0b47b00c0fb648a9977187265d1abe7eb1 100644
--- a/ui/file_manager/file_manager/background/js/test_util_base.js
+++ b/ui/file_manager/file_manager/background/js/test_util_base.js
@@ -8,6 +8,41 @@
 var test = test || {};
 
 /**
+ * Extract the information of the given element.
+ * @param {Element} element Element to be extracted.
+ * @param {Window} contentWindow Window to be tested.
+ * @param {Array.<string>=} opt_styleNames List of CSS property name to be
+ *     obtained.
+ * @return {{attributes:Object.<string, string>, text:string,
+ *                  styles:Object.<string, string>, hidden:boolean}} Element
+ *     information that contains contentText, attribute names and
+ *     values, hidden attribute, and style names and values.
+ */
+function extractElementInfo(element, contentWindow, opt_styleNames) {
+  var attributes = {};
+  for (var i = 0; i < element.attributes.length; i++) {
+    attributes[element.attributes[i].nodeName] =
+        element.attributes[i].nodeValue;
+  }
+  var styles = {};
+  var styleNames = opt_styleNames || [];
+  var computedStyles = contentWindow.getComputedStyle(element);
+  for (var i = 0; i < styleNames.length; i++) {
+    styles[styleNames[i]] = computedStyles[styleNames[i]];
+  }
+  var text = element.textContent;
+  return {
+    attributes: attributes,
+    text: text,
+    value: element.value,
+    styles: styles,
+    // The hidden attribute is not in the element.attributes even if
+    // element.hasAttribute('hidden') is true.
+    hidden: !!element.hidden
+  };
+}
+
+/**
  * Namespace for test utility functions.
  *
  * Public functions in the test.util.sync and the test.util.async namespaces are
@@ -147,31 +182,35 @@ test.util.sync.queryAllElements = function(
   return Array.prototype.map.call(
       doc.querySelectorAll(targetQuery),
       function(element) {
-        var attributes = {};
-        for (var i = 0; i < element.attributes.length; i++) {
-          attributes[element.attributes[i].nodeName] =
-              element.attributes[i].nodeValue;
-        }
-        var styles = {};
-        var styleNames = opt_styleNames || [];
-        var computedStyles = contentWindow.getComputedStyle(element);
-        for (var i = 0; i < styleNames.length; i++) {
-          styles[styleNames[i]] = computedStyles[styleNames[i]];
-        }
-        var text = element.textContent;
-        return {
-          attributes: attributes,
-          text: text,
-          value: element.value,
-          styles: styles,
-          // The hidden attribute is not in the element.attributes even if
-          // element.hasAttribute('hidden') is true.
-          hidden: !!element.hidden
-        };
+        return extractElementInfo(element, contentWindow, opt_styleNames);
       });
 };
 
 /**
+ * Get the information of the active element.
+ *
+ * @param {Window} contentWindow Window to be tested.
+ * @param {string} targetQuery Query to specify the element.
+ * @param {?string} iframeQuery Iframe selector or null if no iframe.
+ * @param {Array.<string>=} opt_styleNames List of CSS property name to be
+ *     obtained.
+ * @return {{attributes:Object.<string, string>, text:string,
+ *                  styles:Object.<string, string>, hidden:boolean}=} Element
+ *     information that contains contentText, attribute names and
+ *     values, hidden attribute, and style names and values. If there is no
+ *     active element, returns null.
+ */
+test.util.sync.getActiveElement = function(
+    contentWindow, targetQuery, iframeQuery, opt_styleNames) {
+  var doc = test.util.sync.getDocument_(
+      contentWindow, iframeQuery || undefined);
+  if (!doc || !doc.activeElement)
+    return null;
+
+  return extractElementInfo(doc.activeElement, contentWindow, opt_styleNames);
+};
+
+/**
  * Assigns the text to the input element.
  * @param {Window} contentWindow Window to be tested.
  * @param {string} query Query for the input element.