Make HTMLMediaElement.setMediaKeys() asynchronous.

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 92d7f982a7819ef461e96984f2addbfa9d6fe6ed..670556b9a8008117ed6ca07bec248ba9bf5d301c 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-setmediakeys.html
@@ -23,24 +23,31 @@
                 assert_equals(typeof video.setMediaKeys, 'function');
 
                 // Try setting mediaKeys to null.
-                video.setMediaKeys(null);
-                assert_equals(video.mediaKeys, null);
+                video.setMediaKeys(null).then(function(result) {
+                    assert_equals(video.mediaKeys, null);
 
-                // Try setting mediaKeys to the wrong type of object.
-                assert_throws(new TypeError(),
-                              function () { video.setMediaKeys(new Date()) });
+                    // Try setting mediaKeys to the wrong type of object.
+                    return video.setMediaKeys(new Date());
+                }).then(function(result) {
+                    assert_unreached('setMediaKeys did not fail when setting to Date()');
+                }, function(error) {
+                    // TypeError expected.
+                    assert_equals(error.name, 'TypeError');
 
-                // Create a MediaKeys object and assign it to video.
-                MediaKeys.create('org.w3.clearkey').then(function(result) {
+                    // Create a MediaKeys object and assign it to video.
+                    return MediaKeys.create('org.w3.clearkey');
+                }).then(function(result) {
                     mediaKeys = result;
                     assert_not_equals(mediaKeys, null);
                     assert_equals(mediaKeys.keySystem, 'org.w3.clearkey');
-                    video.setMediaKeys(mediaKeys);
+                    return video.setMediaKeys(mediaKeys);
+                }).then(function(result) {
                     assert_not_equals(video.mediaKeys, null);
                     assert_true(video.mediaKeys === mediaKeys);
 
                     // Set it a second time.
-                    video.setMediaKeys(mediaKeys);
+                    return video.setMediaKeys(mediaKeys);
+                }).then(function(result) {
                     assert_not_equals(video.mediaKeys, null);
                     assert_true(video.mediaKeys === mediaKeys);
 
@@ -55,26 +62,38 @@
                     assert_equals(mediaKeys2.keySystem, 'org.w3.clearkey');
 
                     // Assign the second MediaKeys to video.
-                    video.setMediaKeys(mediaKeys2);
+                    return video.setMediaKeys(mediaKeys2);
+                }).then(function(result) {
                     assert_not_equals(video.mediaKeys, null);
                     assert_not_equals(video.mediaKeys, mediaKeys);
                     assert_true(video.mediaKeys === mediaKeys2);
 
                     // Set it back to first MediaKeys.
-                    video.setMediaKeys(mediaKeys);
+                    return video.setMediaKeys(mediaKeys);
+                }, function(error) {
+                    // Some implementations don't support changing MediaKeys
+                    // once set, so this test is a success.
+                    // FIXME: Allow this case to pass as necessary before
+                    // submitting to W3C.
+                    assert_equals(error.name, "NotSupportedError");
+                    forceTestFailureFromPromise(test, error);
+                }).then(function(result) {
                     assert_true(video.mediaKeys === mediaKeys);
                     assert_not_equals(video.mediaKeys, mediaKeys2);
 
                     // Set mediaKeys to null.
-                    video.setMediaKeys(null);
+                    return video.setMediaKeys(null);
+                }).then(function(result) {
                     assert_equals(video.mediaKeys, null);
 
                     // Set it to null a second time.
-                    video.setMediaKeys(null);
+                    return video.setMediaKeys(null);
+                }).then(function(result) {
                     assert_equals(video.mediaKeys, null);
 
                     // Set it back to first MediaKeys again.
-                    video.setMediaKeys(mediaKeys);
+                    return video.setMediaKeys(mediaKeys);
+                }).then(function(result) {
                     assert_true(video.mediaKeys === mediaKeys);
                     assert_not_equals(video.mediaKeys, mediaKeys2);
                     test.done();