Bug 927296 - Fix testPrivateBrowsing NullPointerException by waiting for the title placeholder. r=gbrown

mobile/android/base/tests/PixelTest.java.in

@@ -57,6 +57,7 @@ abstract class PixelTest extends BaseTest {
         }
         tabEventExpecter.blockForEvent();
         contentEventExpecter.blockForEvent();
+        waitForText(StringHelper.TITLE_PLACE_HOLDER);
         loadAndPaint(url);
         tabEventExpecter.unregisterListener();
         contentEventExpecter.unregisterListener();

mobile/android/base/tests/StringHelper.java.in

@@ -45,6 +45,8 @@ class StringHelper {
         "Add to Home Screen"
     };
 
+    public static final String TITLE_PLACE_HOLDER = "Enter Search or Address";
+
     // Robocop page urls
     // Note: please use getAbsoluteUrl(String url) on each robocop url to get the correct url
     public static final String ROBOCOP_BIG_LINK_URL = "/robocop/robocop_big_link.html";