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

test/webkit/fast/js/string-link.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 35 matching lines @@
 // Generic use on Number object.
 shouldBe("String.prototype.link.call(0x2A, 0x2A)", '"<a href=\\"42\\">42</a>"');
 
 // Generic use on non-coercible object `undefined`.
 shouldThrow("String.prototype.link.call(undefined)", '"TypeError: Type error"');
 
 // Generic use on non-coercible object `null`.
 shouldThrow("String.prototype.link.call(null)", '"TypeError: Type error"');
 
 // Check link.length.
-shouldBe("String.prototype.link.length", "1");
+shouldBe("String.prototype.link.length", "1");