Add LayoutTests for MediaSource codec config changes.

LayoutTests/http/tests/media/media-source/mediasource-config-changes.js

Index: LayoutTests/http/tests/media/media-source/mediasource-config-changes.js
diff --git a/LayoutTests/http/tests/media/media-source/mediasource-config-changes.js b/LayoutTests/http/tests/media/media-source/mediasource-config-changes.js
new file mode 100644
index 0000000000000000000000000000000000000000..7c17ccfd199cfe6099388760f7b4090f85ca2e6c
--- /dev/null
+++ b/LayoutTests/http/tests/media/media-source/mediasource-config-changes.js
@@ -0,0 +1,78 @@
+function fetchManifestAndData(test, manifestFilename, callback)
+{
+    var baseURL = '/media/resources/media-source/';
+    var manifestURL = baseURL + manifestFilename;
+    MediaSourceUtil.loadTextData(test, manifestURL, function(manifestText)
+    {
+        var manifest = JSON.parse(manifestText);
+
+        assert_true(MediaSource.isTypeSupported(manifest.type), manifest.type + " is supported.");
+
+        var mediaURL = baseURL + manifest.url;
+        MediaSourceUtil.loadBinaryData(test, mediaURL, function(mediaData)
+        {
+            callback(manifest.type, mediaData);
+        });
+    });
+}
+
+function appendBuffer(test, sourceBuffer, data)
+{
+    test.expectEvent(sourceBuffer, "update");
+    test.expectEvent(sourceBuffer, "updateend");
+    sourceBuffer.appendBuffer(data);
+}
+
+function mediaSourceConfigChangeTest(directory, idA, idB, description)
+{
+    var manifestFilenameA = directory + "/test-" + idA + "-manifest.json";
+    var manifestFilenameB = directory + "/test-" + idB + "-manifest.json";
+    mediasource_test(function(test, mediaElement, mediaSource)
+    {
+        mediaElement.pause();
+        test.failOnEvent(mediaElement, 'error');
+        test.endOnEvent(mediaElement, 'ended');
+
+        fetchManifestAndData(test, manifestFilenameA, function(typeA, dataA)
+        {
+            fetchManifestAndData(test, manifestFilenameB, function(typeB, dataB)
+            {
+                assert_equals(typeA, typeB, "Media format types match");
+
+                var sourceBuffer = mediaSource.addSourceBuffer(typeA);
+
+                appendBuffer(test, sourceBuffer, dataA);
+
+                test.waitForExpectedEvents(function()
+                {
+                    // Add the second buffer starting at 0.5 second.
+                    sourceBuffer.timestampOffset = 0.5;
+                    appendBuffer(test, sourceBuffer, dataB);
+                });
+
+                test.waitForExpectedEvents(function()
+                {
+                    // Add the first buffer starting at 1 second.
+                    sourceBuffer.timestampOffset = 1;
+                    appendBuffer(test, sourceBuffer, dataA);
+                });
+
+                test.waitForExpectedEvents(function()
+                {
+                    // Add the second buffer starting at 1.5 second.
+                    sourceBuffer.timestampOffset = 1.5;
+                    appendBuffer(test, sourceBuffer, dataB);
+                });
+
+                test.waitForExpectedEvents(function()
+                {
+                    // Truncate the presentation to a duration of 2 seconds.
+                    mediaSource.duration = 2;
+                    mediaSource.endOfStream();
+
+                    mediaElement.play();
+                });
+            });
+        });
+    }, description, { timeout: 10000 } );
+};