File constructor understands lastModified.

LayoutTests/fast/files/blob-constructor.html

Index: LayoutTests/fast/files/blob-constructor.html
diff --git a/LayoutTests/fast/files/blob-constructor.html b/LayoutTests/fast/files/blob-constructor.html
index f5c125f3b00fe0ed983f02a9416315b05d7e0453..37db35e304ed1ed6f6189117b6300d49f9e03ade 100644
--- a/LayoutTests/fast/files/blob-constructor.html
+++ b/LayoutTests/fast/files/blob-constructor.html
@@ -61,11 +61,17 @@ shouldBeTrue("(new Blob([], [])) instanceof window.Blob");
 shouldBeTrue("(new Blob([], /abc/)) instanceof window.Blob");
 shouldBeTrue("(new Blob([], function () {})) instanceof window.Blob");
 
-// Test that the type/size is correctly added to the Blob
+// Test that the type/size is correctly added to the Blob.
 shouldBe("(new Blob([], {type:'text/html'})).type", "'text/html'");
 shouldBe("(new Blob([], {type:'text/html'})).size", "0");
 shouldBe("(new Blob([], {type:'text/plain;charset=UTF-8'})).type", "'text/plain;charset=utf-8'");
 
+// Test that the File-specific lastModificationDate is not set by the Blob constructor.
+shouldBe("(new Blob([])).lastModifiedDate", "undefined");
+shouldBe("(new Blob([], {})).lastModifiedDate", "undefined");
+shouldBe("(new Blob([], {lastModifiedDate: new Date()})).lastModifiedDate", "undefined");
+shouldBe("(new Blob([], {lastModifiedDate: 'not a valid date'})).lastModifiedDate", "undefined");
+
 // Test the number of expected arguments in the Blob constructor.
 shouldBe("window.Blob.length", "0");