Add LayoutTests for MediaSource codec config changes.

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

+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 mediasource_configchange_test(directory, idA, idB, description)

[adamk, 2013/06/18 21:54:23]

Noticed this when reviewing the tests; why isn't this camelCased?

[acolwell GONE FROM CHROMIUM, 2013/06/18 23:00:18]

I did this just to match mediasource_test, which was intended to match
async_test() in testharness.js. I'll update it to match Blink camelCased style
instead.

+{
+    var manifestFilenameA = directory + "/test-" + idA + "-manifest.json";
+    var manifestFilenameB = directory + "/test-" + idB + "-manifest.json";
+    mediasource_test(function(test, mediaElement, mediaSource)

[adamk, 2013/06/18 21:54:23]

Does it have something to do with the fact that mediasource_test() isn't either?

[acolwell GONE FROM CHROMIUM, 2013/06/18 23:00:18]

Yes. Mind if I defer the renaming of mediasource_test() to mediaSourceTest() to
a separate CL?

[adamk, 2013/06/19 00:22:36]

Deferring is fine, and actually if it matches testharness.js it's probably not
worth changing.

+    {
+        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 } );
+};