MSE: Start letting SourceBuffer begin to do initialization segment received algorithm

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

Index: LayoutTests/http/tests/media/media-source/mediasource-util.js
diff --git a/LayoutTests/http/tests/media/media-source/mediasource-util.js b/LayoutTests/http/tests/media/media-source/mediasource-util.js
index b181cdc5f698c54b274ab0a8c81a380c15e8c97e..ffa6a1e6ece7e7efd11c758d6a9556ed165042dd 100644
--- a/LayoutTests/http/tests/media/media-source/mediasource-util.js
+++ b/LayoutTests/http/tests/media/media-source/mediasource-util.js
@@ -360,7 +360,7 @@
         }, description, options);
     };
 
-    window['mediasource_testafterdataloaded'] = function(testFunction, description, options)
+    window['mediasource_testafterdataloaded_internal'] = function(testFunction, description, failOnMediaElementError, options)
     {
         mediasource_test(function(test, mediaElement, mediaSource)
         {
@@ -371,7 +371,8 @@
                 return;
             }
 
-            test.failOnEvent(mediaElement, 'error');
+            if (failOnMediaElementError)
+                test.failOnEvent(mediaElement, 'error');
 
             var sourceBuffer = mediaSource.addSourceBuffer(segmentInfo.type);
             MediaSourceUtil.loadBinaryData(test, segmentInfo.url, function(mediaData)
@@ -379,7 +380,17 @@
                 testFunction(test, mediaElement, mediaSource, segmentInfo, sourceBuffer, mediaData);
             });
         }, description, options);
-    }
+    };
+
+    window['mediasource_testafterdataloaded'] = function(testFunction, description, options)
+    {
+        mediasource_testafterdataloaded_internal(testFunction, description, true, options);
+    };
+
+    window['mediasource_testafterdataloaded_nofailonerror'] = function(testFunction, description, options)
+    {
+        mediasource_testafterdataloaded_internal(testFunction, description, false, options);
+    };
 
     function timeRangesToString(ranges)
     {