Implement DragEvent and move MouseEvent.dataTransfer

LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html

Index: LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html
diff --git a/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html b/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html
index 5199e09947445ff62fca04262f663d9cf909062a..8116cc5af7a761de69c9e1bc3eb993907171ea9a 100644
--- a/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html
+++ b/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001.html
@@ -12,13 +12,11 @@ test(function() {
 	assert_own_property(window,'DragEvent');
 }, 'window.DragEvent should be exposed' );
 test(function() {

[Rick Byers, 2015/08/06 14:22:32]

These "imported/web-platform-tests" are special, see
https://www.chromium.org/blink/importing-the-w3c-tests.  I don't think we want
to make edits to them here.  The official home is here:
https://github.com/w3c/web-platform-tests/commits/master/html/editing/dnd/syn....

I think it's fine to just update our expectations.  Obviously we didn't exactly
expect this test to pass before, and it still doesn't pass completely.

Of course if you'd also like to contribute improvements to the test back to the
w3c that's great too.  But I wouldn't block this CL on it.

[Jimmy Jo, 2015/08/07 02:42:03]

Done.

- assert_throws('NOT_SUPPORTED_ERR', function() {
  	var evt = document.createEvent('DragEvent');
- });
-}, 'createEvent should not be able to create a DragEvent' );
+}, 'createEvent should be able to create a DragEvent' );
 test(function() {
 	var evt = new DragEvent('dragstart');
-	assert_false( !!evt.initDragEvent, 'initDragEvent' );
+	assert_true( !!evt.initDragEvent, 'initDragEvent' );
 	assert_true( !!evt.initMouseEvent, 'initMouseEvent' );
 	assert_true( !!evt.initUIEvent, 'initUIEvent' );
 	assert_true( !!evt.initEvent, 'initEvent' );
@@ -55,7 +53,7 @@ test(function() {
  assert_throws(new TypeError(), function() {
  	var evt = new DragEvent('dragstart', {dataTransfer:{}});
  });
-}, 'DragEvent constructor with custom object as the dataTransfer parameter should throw TypeError' );
+}, 'DragEvent constructor with custom object as the dataTransfer parameter should not throw TypeError' );
 test(function() {
 	var evt = new DragEvent('dragstart'), div = document.createElement('div'), ranlistener = false;
 	div.ondragstart = function () { ranlistener = true; };
@@ -117,4 +115,4 @@ test(function() {
 		</script>
 		<noscript><p>Enable JavaScript and reload</p></noscript>
 	</body>
-</html>
+</html>