Add W3C encrypted-media tests

third_party/WebKit/LayoutTests/imported/wpt/encrypted-media/scripts/setmediakeys-to-multiple-video-elements.js

+function runTest(config, qualifier) {
+    var testname = testnamePrefix(qualifier, config.keysystem)
+                                 + ', setMediaKeys to multiple video elements';
+
+    var configuration = getSimpleConfigurationForContent(config.content);
+
+    if ( config.initDataType && config.initData ) {
+        configuration.initDataTypes = [ config.initDataType ];
+    }
+
+    async_test (function (test) {
+        var _video1 = config.video1,
+            _video2 = config.video2,
+            _mediaKeys;
+
+        function onFailure(error) {
+            forceTestFailureFromPromise(test, error);
+        }
+
+        navigator.requestMediaKeySystemAccess(config.keysystem, [configuration]).then(function(access) {
+            assert_equals(access.keySystem, config.keysystem)
+            return access.createMediaKeys();
+        }).then(function(result) {
+            _mediaKeys = result;
+            assert_not_equals(_mediaKeys, null);
+            assert_equals(typeof _mediaKeys.createSession, 'function');
+            return _video1.setMediaKeys(_mediaKeys);
+        }).then(function(result) {
+            assert_not_equals(_video1.mediaKeys, null);
+            assert_true(_video1.mediaKeys === _mediaKeys);
+            // The specification allows this to fail, but it is not required to fail.
+            return _video2.setMediaKeys(_mediaKeys);
+        }).then(function(result) {
+            // Second setMediaKeys is not required to fail.
+            assert_true(_video2.mediaKeys === _mediaKeys);
+            return Promise.resolve();
+        }, function(error) {
+            assert_equals(error.name, 'QuotaExceededError');
+            assert_not_equals(error.message, '');
+            // Return something so the promise resolves properly.
+            return Promise.resolve();
+        }).then(function() {
+            // Now clear it from video1.
+            return _video1.setMediaKeys(null);
+        }).then(function() {
+            // Should be assignable to video2.
+            return _video2.setMediaKeys(_mediaKeys);
+        }).then(function(result) {
+            assert_not_equals(_video2.mediaKeys, null);
+            assert_true(_video2.mediaKeys === _mediaKeys);
+            test.done();
+        }).catch(onFailure);
+    }, testname);
+}