Add new "resize" event to HTMLMediaElement.

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

+// Extract & return the resolution string from a filename, if any.
+function resolutionFromFilename(filename)
+{
+    resolution = filename.replace(/^.*[^0-9]([0-9]+x[0-9]+)[^0-9].*$/, "$1");
+    if (resolution != filename) {
+        return resolution;
+    }
+    return "";
+}
+
 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');
+        var expectResizeEvents = resolutionFromFilename(manifestFilenameA) != resolutionFromFilename(manifestFilenameB);
+        var expectedResizeEventCount = 0;
 
         MediaSourceUtil.fetchManifestAndData(test, manifestFilenameA, function(typeA, dataA)
         {
             MediaSourceUtil.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);
+                    ++expectedResizeEventCount;
                 });
 
                 test.waitForExpectedEvents(function()
                 {
                     // Add the first buffer starting at 1 second.
                     sourceBuffer.timestampOffset = 1;
                     appendBuffer(test, sourceBuffer, dataA);
+                    ++expectedResizeEventCount;
                 });
 
                 test.waitForExpectedEvents(function()
                 {
                     // Add the second buffer starting at 1.5 second.
                     sourceBuffer.timestampOffset = 1.5;
                     appendBuffer(test, sourceBuffer, dataB);
+                    ++expectedResizeEventCount;
                 });
 
                 test.waitForExpectedEvents(function()
                 {
                     // Truncate the presentation to a duration of 2 seconds.
                     mediaSource.duration = 2;
                     mediaSource.endOfStream();
 
+                    if (expectResizeEvents) {
+                        for (var i = 0; i < expectedResizeEventCount; ++i) {
+                            test.expectEvent(mediaElement, "resize");
+                        }
+                    }
+                    test.expectEvent(mediaElement, "ended");
                     mediaElement.play();
                 });
+
+                test.waitForExpectedEvents(function() {
+                    test.done();
+                });
             });
         });
     }, description, { timeout: 10000 } );
 };