Layout Test for basic MSE seek scenario.

LayoutTests/http/tests/media/media-source/mediasource-util.js

 (function(window) {
     EventExpectationsManager = function(test)
     {
         this.test_ = test;
         this.eventTargetList_ = [];
         this.waitCallbacks_ = [];
     };
 
     EventExpectationsManager.prototype.expectEvent = function(object, eventName, description)
     {
@@ skipping 163 matching lines @@
         test.expectEvent = function(object, eventName, description)
         {
             test.eventExpectations_.expectEvent(object, eventName, description);
         };
 
         test.waitForExpectedEvents = function(callback)
         {
             test.eventExpectations_.waitForExpectedEvents(callback);
         };
 
+        test.waitForCurrentTimeChange = function(mediaElement, callback)
+        {
+            var initialTime = mediaElement.currentTime;
+
+            var onTimeUpdate = test.step_func(function()
+            {
+                if (mediaElement.currentTime != initialTime) {
+                    mediaElement.removeEventListener('timeupdate', onTimeUpdate);
+                    callback();
+                }
+            });
+
+            mediaElement.addEventListener('timeupdate', onTimeUpdate);
+        }
+
         var oldTestDone = test.done.bind(test);
         test.done = function()
         {
-            if (test.status == test.PASS)
+            if (test.status == test.PASS) {
                 assert_false(test.eventExpectations_.expectingEvents(), "No pending event expectations.");
+            }
             oldTestDone();
         };
     };
 
     window['MediaSourceUtil'] = MediaSourceUtil;
     window['media_test'] = function(testFunction, description, options)
     {
         options = options || {};
         return async_test(function(test)
         {
@@ skipping 21 matching lines @@
             };
 
             openMediaSource_(test, mediaTag, function(mediaSource)
             {
                 testFunction(test, mediaTag, mediaSource);
             });
         }, description, options);
 
     };
 })(window);