Add sandbox support for associating peer processes

sandbox/src/sandbox.h

Index: sandbox/src/sandbox.h
===================================================================
--- sandbox/src/sandbox.h	(revision 132034)
+++ sandbox/src/sandbox.h	(working copy)
@@ -84,6 +84,14 @@
   //   If the return is ERROR_GENERIC, you can call ::GetLastError() to get
   //   more information.
   virtual ResultCode WaitForAllTargets() = 0;
+
+  // Adds an unsandboxed process as a peer for policy decisions (e.g.
+  // HANDLES_DUP_ANY policy).
+  // Returns:
+  //   ALL_OK if successful. All other return values imply failure.
+  //   If the return is ERROR_GENERIC, you can call ::GetLastError() to get
+  //   more information.
+  virtual ResultCode AddTargetPeer(HANDLE peer_process) = 0;
 };
 
 // TargetServices models the current process from the perspective