Add guard pages in front of platform allocations

src/platform-win32.cc

Index: src/platform-win32.cc
===================================================================
--- src/platform-win32.cc	(revision 8619)
+++ src/platform-win32.cc	(working copy)
@@ -938,7 +938,6 @@
   USE(size);
 }
 
-
 #ifdef ENABLE_HEAP_PROTECTION
 
 void OS::Protect(void* address, size_t size) {
@@ -955,9 +954,14 @@
   VirtualProtect(address, size, new_protect, &old_protect);
 }
 
-#endif
+void OS::Guard(void* address, const size_t size) {
+  DWORD oldprotect;
+  VirtualProtect(address, size, PAGE_READONLY | PAGE_GUARD, &oldprotect);
+}
 
+#endif  // ENABLE_HEAP_PROTECTION
 
+
 void OS::Sleep(int milliseconds) {
   ::Sleep(milliseconds);
 }