Make length property return useful values for DOM bindings functions

LayoutTests/fast/js/constructor-length.html

Index: LayoutTests/fast/js/constructor-length.html
diff --git a/LayoutTests/fast/js/constructor-length.html b/LayoutTests/fast/js/constructor-length.html
index 1d4e46a2ca0e7c9d14949d88f16cf34a1775237d..5fa89e69cf4ebef077b3dc4aec388fda400a998e 100644
--- a/LayoutTests/fast/js/constructor-length.html
+++ b/LayoutTests/fast/js/constructor-length.html
@@ -9,22 +9,22 @@ description("This tests the length property of constructors.");
 
 shouldBe('ArrayBuffer.length', '1');
 shouldBe('AudioContext.length', '0');
-shouldBe('AutocompleteErrorEvent.length', '2');
-shouldBe('BeforeLoadEvent.length', '2');
-shouldBe('Blob.length', '2');
-shouldBe('CloseEvent.length', '2');
-shouldBe('CustomEvent.length', '2');
+shouldBe('AutocompleteErrorEvent.length', '1');
+shouldBe('BeforeLoadEvent.length', '1');
+shouldBe('Blob.length', '0');
+shouldBe('CloseEvent.length', '1');
+shouldBe('CustomEvent.length', '1');
 shouldBe('DOMFormData.length', '0');
 shouldBe('DOMParser.length', '0');
-shouldBe('DataView.length', '3');
-shouldBe('ErrorEvent.length', '2');
-shouldBe('Event.length', '2');
-shouldBe('EventSource.length', '2');
+shouldBe('DataView.length', '1');
+shouldBe('ErrorEvent.length', '1');
+shouldBe('Event.length', '1');
+shouldBe('EventSource.length', '1');
 shouldBe('Float32Array.length', '1');
 shouldBe('Float64Array.length', '1');
 shouldBe('FileReader.length', '0');
 shouldBe('FileReaderSync.length', '0');
-shouldBe('HashChangeEvent.length', '2');
+shouldBe('HashChangeEvent.length', '1');
 shouldBe('Int16Array.length', '1');
 shouldBe('Int32Array.length', '1');
 shouldBe('Int8Array.length', '1');
@@ -32,27 +32,27 @@ shouldBe('Intent.length', '3');
 shouldBe('MediaController.length', '0');
 shouldBe('MediaStream.length', '0');
 shouldBe('MessageChannel.length', '0');
-shouldBe('MessageEvent.length', '2');
-shouldBe('OverflowEvent.length', '2');
-shouldBe('PageTransitionEvent.length', '2');
+shouldBe('MessageEvent.length', '1');
+shouldBe('OverflowEvent.length', '1');
+shouldBe('PageTransitionEvent.length', '1');
 shouldBe('PeerConnection.length', '2');
-shouldBe('PopStateEvent.length', '2');
-shouldBe('ProgressEvent.length', '2');
+shouldBe('PopStateEvent.length', '1');
+shouldBe('ProgressEvent.length', '1');
 shouldBe('ShadowRoot.length', '1');
 shouldBe('SharedWorker.length', '2');
-shouldBe('StorageEvent.length', '2');
+shouldBe('StorageEvent.length', '1');
 shouldBe('TextTrackCue.length', '3');
-shouldBe('TrackEvent.length', '2');
+shouldBe('TrackEvent.length', '1');
 shouldBe('Uint16Array.length', '1');
 shouldBe('Uint32Array.length', '1');
 shouldBe('Uint8Array.length', '1');
 shouldBe('Uint8ClampedArray.length', '1');
-shouldBe('WebGLContextEvent.length', '2');
-shouldBe('WebKitAnimationEvent.length', '2');
-shouldBe('WebKitCSSMatrix.length', '1');
+shouldBe('WebGLContextEvent.length', '1');
+shouldBe('WebKitAnimationEvent.length', '1');
+shouldBe('WebKitCSSMatrix.length', '0');
 shouldBe('WebKitMutationObserver.length', '1');
-shouldBe('WebKitPoint.length', '2');
-shouldBe('WebKitTransitionEvent.length', '2');
+shouldBe('WebKitPoint.length', '0');
+shouldBe('WebKitTransitionEvent.length', '1');
 shouldBe('WebSocket.length', '1');
 shouldBe('Worker.length', '1');
 shouldBe('URL.length', '0');