Make sure files end with exactly one new line and police this in presubmit.

test/webkit/dfg-weak-js-constant-silent-fill.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 // 1.  Redistributions of source code must retain the above copyright
 //     notice, this list of conditions and the following disclaimer.
 // 2.  Redistributions in binary form must reproduce the above copyright
 //     notice, this list of conditions and the following disclaimer in the
@@ skipping 27 matching lines @@
 
 for (var i = 0; i < 1000; ++i) {
     var o1 = new Object();
     var o2 = new Object();
     var o3 = new Object();
     eval(Empty + "foo(o1, o2, o3, \"stuff\")");
     shouldBe("o1.f", "42");
     shouldBe("o2.f", "false");
     shouldBe("o3.f", "false");
 }
-