Properly implement OS::GetRandomMmapAddr() for Win32.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/20953002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15919 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-win32.cc

@@ -892,7 +892,7 @@ size_t OS::AllocateAlignment() {
 }
 
 
-static void* GetRandomAddr() {
+void* OS::GetRandomMmapAddr() {
   Isolate* isolate = Isolate::UncheckedCurrent();
   // Note that the current isolate isn't set up in a call path via
   // CpuFeatures::Probe. We don't care about randomization in this case because