feat(protractor): add clone methods for ElementFinder and ElementArrayFinder

Author: hankduan

lib/protractor.js

@@ -142,6 +142,19 @@ var buildElementHelper = function(ptor) {
   };
   util.inherits(ElementArrayFinder, webdriver.promise.Promise);
 
+  /**
+   * Create a shallow copy of ElementArrayFinder.
+   *
+   * @return {!ElementArrayFinder} A shallow copy of this.
+   */
+  ElementArrayFinder.prototype.clone = function() {
+    // A shallow copy is all we need since the underlying fields can never be
+    // modified. (Locator can be modified by the user, but that should
+    // rarely/never happen and it doesn't affect functionalities).
+    return new ElementArrayFinder(
+      this.getWebElements, this.locator_, this.actionResults_); 
+  };
+
   /**
    * Calls to ElementArrayFinder may be chained to find an array of elements
    * using the current elements in this ElementArrayFinder as the starting point.
@@ -722,6 +735,17 @@ var buildElementHelper = function(ptor) {
   };
   util.inherits(ElementFinder, webdriver.promise.Promise);
 
+  /**
+   * Create a shallow copy of ElementFinder.
+   *
+   * @return {!ElementFinder} A shallow copy of this.
+   */
+  ElementFinder.prototype.clone = function() {
+    // A shallow copy is all we need since the underlying fields can never be
+    // modified 
+    return new ElementFinder(this.parentElementArrayFinder); 
+  };
+
   /**
    * See ElementArrayFinder.prototype.locator
    * @return {webdriver.Locator}