MSE: Add layout test for 'decode' error via an algorithm

LayoutTests/http/tests/media/media-source/mediasource-errors.html

Index: LayoutTests/http/tests/media/media-source/mediasource-errors.html
diff --git a/LayoutTests/http/tests/media/media-source/mediasource-errors.html b/LayoutTests/http/tests/media/media-source/mediasource-errors.html
index bb839522155b8a2d222ba16f977886464d8a5c76..b9908ad8aebaa389f5875b4049992086ad2369df 100644
--- a/LayoutTests/http/tests/media/media-source/mediasource-errors.html
+++ b/LayoutTests/http/tests/media/media-source/mediasource-errors.html
@@ -143,6 +143,28 @@
                     test.done();
                 });
             }, "Signaling 'network' error via endOfStream() after initialization segment has been appended and the HTMLMediaElement has reached HAVE_METADATA.");
+
+            ErrorTest(function(test, mediaElement, mediaSource, segmentInfo, sourceBuffer, mediaData)
+            {
+                assert_equals(mediaElement.readyState, HTMLMediaElement.HAVE_NOTHING);
+
+                var mediaSegment = MediaSourceUtil.extractSegmentData(mediaData, segmentInfo.media[0]);
+                var index = segmentInfo.init.size + (mediaSegment.length - 1) / 2;
+                // Corrupt the media data from index of mediaData, so it can signal 'decode' error.
+                // Here use mediaSegment to replace the original mediaData[index, index + mediaSegment.length]
+                mediaData.set(mediaSegment, index);
+
+                test.expectEvent(mediaElement, "error", "mediaElement error.");
+                sourceBuffer.appendBuffer(mediaData);
+
+                test.waitForExpectedEvents(function()
+                {
+                    assert_equals(mediaElement.readyState, HTMLMediaElement.HAVE_METADATA);
+                    assert_true(mediaElement.error != null);
+                    assert_equals(mediaElement.error.code, MediaError.MEDIA_ERR_DECODE);
+                    test.done();
+                });
+            }, "Signaling 'decode' error via segment parser loop algorithm after initialization segment and partial media segment has been appended.");
         </script>
     </body>
 </html>