Throw DataCloneError on cloning closed Blobs/Files.

LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js

Index: LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js
diff --git a/LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js b/LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js
index 2ee8ca14ce6b9a096e2f6059b928b557cf5ef500..645a85ce28fbcf400450166e29d81c3a7d9fa43a 100644
--- a/LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js
+++ b/LayoutTests/fast/dom/Window/script-tests/postmessage-clone.js
@@ -75,6 +75,18 @@ tryPostMessage('mutatedImageData.data', false, imageData.data)
 for (var i = 0; i < imageData.data.length * 4; i++)
     mutatedImageData.data[i] = 0;
 
+// Test close() special case for Blob (and File.)
+
+var blob = new Blob(["Hello"]);
+var blobSize = blob.size;
+tryPostMessage('blob', false, "evalThunk", function(v) { doPassFail(v.size === blobSize, "Cloned Blob size equal to the original size."); });
+tryPostMessage('blob.close(); blob', true, null, DOMException.DATA_CLONE_ERR);
+
+var constructedFile = new File(["Hello"], "test");
+var fileSize = constructedFile.size;
+tryPostMessage('constructedFile', false, "evalThunk", function(v) { doPassFail(v.size === fileSize, "Cloned File size equal to the original size."); });
+tryPostMessage('constructedFile.close(); constructedFile', true, null, DOMException.DATA_CLONE_ERR);
+
 function thunk(s) {
     return "(function() {" + s + "})()";
 }