fix(element): fix WebElement.$ using the incorrect By object

Closes #852

Author: juliemr

lib/protractor.js

@@ -671,8 +671,8 @@ Protractor.prototype.wrapWebElement = function(element) {
    * @return {!webdriver.WebElement}
    */
   element.$ = function(selector) {
-    var locator = thisPtor.By.css(selector);
-    return this.findElement(locator);
+    var locator = webdriver.By.css(selector);
+    return thisPtor.findElement(locator);
   };
 
   /**
@@ -718,8 +718,8 @@ Protractor.prototype.wrapWebElement = function(element) {
    *     array of the located {@link webdriver.WebElement}s.
    */
   element.$$ = function(selector) {
-    var locator = thisPtor.By.css(selector);
-    return this.findElements(locator);
+    var locator = webdriver.By.css(selector);
+    return thisPtor.findElements(locator);
   };
 
   /**