Oilpan: Improve address space randomization for the Oilpan heap.

Source/wtf/AddressSpaceRandomization.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WTF_AddressSpaceRandomization_h
+#define WTF_AddressSpaceRandomization_h
+
+#include "wtf/WTFExport.h"
+
+namespace WTF {
+
+// Calculates a random preferred mapping address. In calculating an
+// address, we balance good ASLR against not fragmenting the address
+// space too badly.
+WTF_EXPORT void* getRandomPageBase();
+
+}
+
+#endif