Media Session: MediaMetadata constructor may have 0 parameters.

third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html

Index: third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html
diff --git a/third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html b/third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html
index bfa59ba54a196f2ae4e89cfe5a9a42d095e4d9d4..a94f53171a6b53b7c78e940ac2bc562d81bcdc6a 100644
--- a/third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html
+++ b/third_party/WebKit/LayoutTests/media/mediasession/mediasessionmetadata.html
@@ -8,24 +8,16 @@
     var metadata = new MediaMetadata({});
     assert_not_equals(metadata, null);
 
-    var exception = false;
-    try {
-      metadata = new MediaMetadata("foobar");
-    } catch (e) {
-      exception = true;
-    }
-    assert_true(exception);
-
-    exception = false;
-    try {
-      metadata = new MediaMetadata(42);
-    } catch (e) {
-      exception = true;
-    }
-    assert_true(exception);
+    assert_throws(new TypeError(), _ => new MediaMetadata('foobar'));
+    assert_throws(new TypeError(), _ => new MediaMetadata(42));
   }, 'Test that MediaMetadata is constructed using a dictionary');
 
   test(function() {
+    var metadata = new MediaMetadata();
+    assert_not_equals(metadata, null);
+  }, "Test that MediaMetadata constructor can take no parameter");
+
+  test(function() {
     var metadata = new MediaMetadata({
         title: 'foo', album: 'bar', artist: 'plop',
         artwork: [ { src: 'src1', sizes: 'sizes1', type: 'type1'},
@@ -51,7 +43,15 @@
     assert_equals(metadata.artist, '');
     assert_equals(metadata.album, '');
     assert_equals(0, metadata.artwork.length);
-  }, 'Test the default values for MediaMetadata');
+  }, 'Test the default values for MediaMetadata with empty init dictionary');
+
+  test(function() {
+    var metadata = new MediaMetadata();
+    assert_equals(metadata.title, '');
+    assert_equals(metadata.artist, '');
+    assert_equals(metadata.album, '');
+    assert_equals(0, metadata.artwork.length);
+  }, 'Test the default values for MediaMetadata with no init dictionary');
 
   test(function() {
     var metadata = new MediaMetadata({ randomValueThatWillNotBeAdded: '... hopefully ;)' });