Added Crankshaft support for setters.

test/mjsunit/regress/regress-crbug-125148.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 48 matching lines @@
 
 C = Object.create(B);
 
 function boo(x) { return x.baz; }
 
 assertEquals(111, boo(C));
 assertEquals(111, boo(C));
 ToDictionaryMode(B);
 %OptimizeFunctionOnNextCall(boo);
 assertEquals(111, boo(C));
+
+// And once more for setters...
+A = {};
+Object.defineProperty(A, "huh", { set: function(x) { assertUnreachable(); }});
+
+B = Object.create(A);
+var setterValue;
+Object.defineProperty(B, "huh", { set: function(x) { setterValue = x; }});
+
+C = Object.create(B);
+
+function fuu(x) {
+  setterValue = 222;
+  x.huh = 111;
+  return setterValue;
+}
+
+assertEquals(111, fuu(C));
+assertEquals(111, fuu(C));
+ToDictionaryMode(B);
+%OptimizeFunctionOnNextCall(fuu);
+assertEquals(111, fuu(C));