Use requestMediaKeySystemAccess() to check type support in EME layout tests

LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html

Index: LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html b/LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html
index 340db69d3f2797cbb14b19b6840725f5b11d0c8c..edaef98c493e80619342b0bb623cbd884f083f37 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-clear-key-invalid-license.html
@@ -11,6 +11,8 @@
         <script>
             async_test(function(test)
             {
+                var initDataType;
+                var initData;
                 var invalidLicense = new Uint8Array(
                     [0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77]);
 
@@ -28,12 +30,16 @@
                     });
                 }
 
-                navigator.requestMediaKeySystemAccess('org.w3.clearkey', [{}]).then(function(access) {
+                getSupportedInitDataType().then(function(type) {
+                    initDataType = type;
+                    initData = getInitData(initDataType);
+                    return navigator.requestMediaKeySystemAccess('org.w3.clearkey', [{}]);
+                }).then(function(access) {
                     return access.createMediaKeys();
                 }).then(function(mediaKeys) {
                     var keySession = mediaKeys.createSession();
                     keySession.addEventListener('message', handleMessage, false);
-                    keySession.generateRequest(getInitDataType(), getInitData(getInitDataType()));
+                    keySession.generateRequest(initDataType, initData);
                 }).catch(function(error) {
                     forceTestFailureFromPromise(test, error);
                 });