Implement DragEvent and move MouseEvent.dataTransfer

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

Index: LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001-expected.txt
diff --git a/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001-expected.txt b/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001-expected.txt
index 371da15cb7fb330aa106baafeff19f64e5e96871..c1f702cd1622ccda8f32e89e12ecbe908de19db5 100644
--- a/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001-expected.txt
+++ b/LayoutTests/imported/web-platform-tests/html/editing/dnd/synthetic/001-expected.txt
@@ -1,21 +1,20 @@
 This is a testharness.js-based test.
-FAIL window.DragEvent should be exposed assert_own_property: expected property "DragEvent" missing
-PASS createEvent should not be able to create a DragEvent 
-FAIL DragEvent should have all of the inherited init*Event methods DragEvent is not defined
-FAIL initMouseEvent should not throw DragEvent is not defined
-FAIL initUIEvent should not throw DragEvent is not defined
-FAIL initEvent should not throw DragEvent is not defined
-FAIL DragEvent constructor with null as the dataTransfer parameter should be able to fire the event DragEvent is not defined
-FAIL DragEvent constructor with undefined as the dataTransfer parameter should be able to fire the event DragEvent is not defined
-FAIL DragEvent constructor with custom object as the dataTransfer parameter should throw TypeError assert_throws: function "function () {
- 	var evt = new DragEvent('dragstart', {dat..." threw object "ReferenceError: DragEvent is not defined" ("ReferenceError") expected object "TypeError" ("TypeError")
-FAIL initMouseEvent should be able to fire the event DragEvent is not defined
-FAIL initUIEvent should be able to fire the event DragEvent is not defined
-FAIL initEvent should be able to fire the event DragEvent is not defined
-FAIL DragEvent constructor with null as the dataTransfer parameter should give null as the dataTransfer DragEvent is not defined
-FAIL DragEvent constructor with undefined as the dataTransfer parameter should give null as the dataTransfer DragEvent is not defined
-FAIL initMouseEvent should give null as the dataTransfer DragEvent is not defined
-FAIL initUIEvent should give null as the dataTransfer DragEvent is not defined
-FAIL initEvent should give null as the dataTransfer DragEvent is not defined
+PASS window.DragEvent should be exposed 
+PASS createEvent should be able to create a DragEvent 
+FAIL DragEvent should have all of the inherited init*Event methods assert_true: initDragEvent expected true got false
+PASS initMouseEvent should not throw 
+PASS initUIEvent should not throw 
+PASS initEvent should not throw 
+PASS DragEvent constructor with null as the dataTransfer parameter should be able to fire the event 
+PASS DragEvent constructor with undefined as the dataTransfer parameter should be able to fire the event 
+PASS DragEvent constructor with custom object as the dataTransfer parameter should not throw TypeError 
+PASS initMouseEvent should be able to fire the event 
+PASS initUIEvent should be able to fire the event 
+PASS initEvent should be able to fire the event 
+PASS DragEvent constructor with null as the dataTransfer parameter should give null as the dataTransfer 
+PASS DragEvent constructor with undefined as the dataTransfer parameter should give null as the dataTransfer 
+PASS initMouseEvent should give null as the dataTransfer 
+PASS initUIEvent should give null as the dataTransfer 
+PASS initEvent should give null as the dataTransfer 
 Harness: the test ran to completion.