Use [StrictTypeChecking] for HTMLMediaElement.setMediaKeys

LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html

Index: LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html b/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
index f33a3b524baf9fabb6bc79993de80841ffa54351..f4d195e929f4ce93da7b44c897933ca187c69463 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
@@ -19,6 +19,9 @@
                 run('video.setMediaKeys(null)');
                 testExpected('video.mediaKeys', null);
 
+                consoleWrite("Try setting mediaKeys to the wrong type of object.");
+                testException('video.setMediaKeys(new Date())', '"TypeError: Failed to execute \'setMediaKeys\' on \'HTMLMediaElement\': parameter 1 is not of type \'MediaKeys\'."');
+
                 consoleWrite("Create a MediaKeys object and assign it to video.");
                 run('mediaKeys = new MediaKeys("org.w3.clearkey")');
                 testExpected('mediaKeys', null, '!=');