Add protractor button text locators.

angular-protractor/angular-protractor-tests.ts

@@ -223,6 +223,8 @@ function TestLocatorStrategies() {
     webElement = ptor.findElement(protractor.By.model('model'));
     webElement = ptor.findElement(protractor.By.textarea('textarea'));
     webElement = ptor.findElement(protractor.By.repeater('repeater'));
+    webElement = ptor.findElement(protractor.By.buttonText('buttonText'));
+    webElement = ptor.findElement(protractor.By.partialButtonText('partialButtonText'));
 }
 
 // This function tests the methods that were added to the base WebElement class

angular-protractor/angular-protractor.d.ts

@@ -646,6 +646,10 @@ declare module protractor {
          * var rows = element(by.repeater("cat in pets"));
          */
         repeater(repeatDescriptor: string): webdriver.Locator;
+
+        buttonText(searchText: string): webdriver.Locator;
+
+        partialButtonText(searchText: string): webdriver.Locator;
     }
 
     var By: IProtractorLocatorStrategy;