Add W3C encrypted-media tests

third_party/WebKit/LayoutTests/imported/wpt/encrypted-media/scripts/setmediakeys-again-after-playback.js

+function runTest(config, qualifier) {
+    var testname = testnamePrefix(qualifier, config.keysystem)
+                                    + ', setmediakeys again after playback';
+
+    var configuration = getSimpleConfigurationForContent(config.content);
+
+    if (config.initDataType && config.initData) {
+        configuration.initDataTypes = [config.initDataType];
+    }
+
+    async_test(function(test) {
+        var _video = config.video,
+            _access,
+            _mediaKeys,
+            _mediaKeySession,
+            _mediaSource;
+
+        function onFailure(error) {
+            forceTestFailureFromPromise(test, error);
+        }
+
+        function onMessage(event) {
+            config.messagehandler(event.messageType, event.message).then( function(response) {
+                _mediaKeySession.update(response).catch(onFailure).then(function() {
+                    _video.play();
+                });
+            });
+        }
+
+        function onEncrypted(event) {
+            waitForEventAndRunStep('message', _mediaKeySession, onMessage, test);
+            _mediaKeySession.generateRequest(   config.initData ? config.initDataType : event.initDataType,
+                                                config.initData || event.initData )
+            .catch(onFailure);
+        }
+
+        function playVideo()
+        {
+            return new Promise(function(resolve) {
+                _mediaKeySession = _mediaKeys.createSession('temporary');
+                waitForEventAndRunStep('encrypted', _video, onEncrypted, test);
+                _video.src = URL.createObjectURL(_mediaSource);
+                resolve('success');
+            });
+        }
+
+        navigator.requestMediaKeySystemAccess(config.keysystem, [configuration]).then(function(access) {
+            _access = access;
+            return _access.createMediaKeys();
+        }).then(function(result) {
+            _mediaKeys = result;
+            return _video.setMediaKeys(_mediaKeys);
+        }).then(function() {
+            return config.servercertificate ? _mediaKeys.setServerCertificate( config.servercertificate ) : true;
+        }).then(function( success ) {
+            return testmediasource(config);
+        }).then(function(source) {
+            _mediaSource = source;
+            return playVideo();
+        }).then(function(results) {
+            return _access.createMediaKeys();
+        }).then(function(result) {
+            _mediaKeys = result;
+            return waitForEvent('playing', _video);
+        }).then(test.step_func(function(result) {
+            assert_false(_video.ended);
+            return _video.setMediaKeys(_mediaKeys);
+        })).then(function() {
+            // Able to change MediaKeys while playing.
+            // This is not required to fail.
+            _video.src='';
+            test.done();
+        }, test.step_func(function(error) {
+            assert_in_array(error.name, ['InvalidStateError','NotSupportedError']);
+            _video.src='';
+            test.done();
+        })).catch(onFailure);
+    }, testname);
+}