Add W3C encrypted-media tests

third_party/WebKit/LayoutTests/imported/wpt/encrypted-media/scripts/reset-src-after-setmediakeys.js

+function runTest(config)
+{
+    async_test(function(test) {
+        var mediaKeys;
+        var mediaSource;
+        var encryptedEventIndex = 0;
+        var video = config.video;
+        var keysystem = config.keysystem;
+        var configuration = {
+            initDataTypes: [config.initDataType],
+            audioCapabilities: [{
+                contentType: config.audioType
+            }],
+            videoCapabilities: [{
+                contentType: config.videoType
+            }],
+            sessionTypes: ['temporary']
+        };
+
+        assert_not_equals(video, null);
+
+        var onEncrypted = function(event) {
+            ++encryptedEventIndex;
+            assert_equals(video.mediaKeys, mediaKeys);
+
+            // This event is fired once for the audio stream and once
+            // for the video stream each time .src is set.
+            if (encryptedEventIndex === 2) {
+                // Finished first video; Create new media source and wait for two more encrypted events
+                return testmediasource(config).then(function (source) {
+                    video.src = URL.createObjectURL(source);
+                }).catch(function (error) {
+                    forceTestFailureFromPromise(test, error)
+                });
+            } else if (encryptedEventIndex === 4) {
+                // Finished second video.
+                test.done();
+            }
+        };
+
+        // Create a MediaKeys object and assign it to video.
+        return navigator.requestMediaKeySystemAccess(keysystem, [configuration]).then(test.step_func(function (access) {
+            assert_equals(access.keySystem, keysystem);
+            return access.createMediaKeys();
+        })).then(test.step_func(function (result) {
+            mediaKeys = result;
+            assert_not_equals(mediaKeys, null);
+            return video.setMediaKeys(mediaKeys);
+        })).then(test.step_func(function () {
+            assert_equals(video.mediaKeys, mediaKeys);
+            return testmediasource(config);
+        })).then(function (source) {
+            waitForEventAndRunStep('encrypted', video, onEncrypted, test);
+            mediaSource = source;
+            video.src = URL.createObjectURL(mediaSource);
+        }).catch(function (error) {
+            forceTestFailureFromPromise(test, error);
+        });
+
+    }, 'Reset src after setMediaKeys().');
+}