ipc: Create an unforgeable mechanism to get the process id of the sender.

ipc/ipc_channel_win.cc

 // Copyright (c) 2012 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.
 
 #include "ipc/ipc_channel_win.h"
 
 #include <windows.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 225 matching lines @@
 
   peer_pid_ = claimed_pid;
   // Validation completed.
   validate_client_ = false;
 
   FlushPrelimQueue();
 
   listener()->OnChannelConnected(claimed_pid);
 }
 
+base::ProcessId ChannelWin::GetSenderPID() {
+  return GetPeerPID();
+}
+
 bool ChannelWin::DidEmptyInputBuffers() {
   // We don't need to do anything here.
   return true;
 }
 
 // static
 const base::string16 ChannelWin::PipeName(
     const std::string& channel_id, int32* secret) {
   std::string name("\\\\.\\pipe\\chrome.");
 
@@ skipping 308 matching lines @@
   int secret;
   do {  // Guarantee we get a non-zero value.
     secret = base::RandInt(0, std::numeric_limits<int>::max());
   } while (secret == 0);
 
   id.append(GenerateUniqueRandomChannelID());
   return id.append(base::StringPrintf("\\%d", secret));
 }
 
 }  // namespace IPC