Provide access to the ID for the remoted Windows session in the network process

remoting/host/desktop_session_proxy.cc

Index: remoting/host/desktop_session_proxy.cc
diff --git a/remoting/host/desktop_session_proxy.cc b/remoting/host/desktop_session_proxy.cc
index 636c177695e2114ff538339108783cb4b53337ae..ed7ba98793e6048cad24942bfb4bb5dbd6f1220b 100644
--- a/remoting/host/desktop_session_proxy.cc
+++ b/remoting/host/desktop_session_proxy.cc
@@ -200,6 +200,13 @@ void DesktopSessionProxy::OnChannelConnected(int32_t peer_pid) {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   VLOG(1) << "IPC: network <- desktop (" << peer_pid << ")";
+
+#if defined(OS_WIN)
+  if (!ProcessIdToSessionId(peer_pid,

[Sergey Ulanov, 2016/06/23 22:35:53]

Can we assume that the session_id will never change for duration of the session?

[joedow, 2016/06/23 23:26:04]

The session ID will never change for the desktop_host/remoting_host process the
proxy is connected to.  Sessions do change, but a new process/proxy is created
and used by the network process when that occurs.

+                            reinterpret_cast<DWORD*>(&desktop_session_id_))) {

[Sergey Ulanov, 2016/06/23 22:35:53]

Do you need this cast? DWORD should be equivalent to uint32_t, so I don't think
it's necessary.

[joedow, 2016/06/23 23:26:04]

You would think it would be unnecessary but compilation fails if I don't:
remoting\host\desktop_session_proxy.cc(205): error C2664: 'BOOL
ProcessIdToSessionId(DWORD,DWORD *)': cannot convert argument 2 from 'uint32_t
*' to 'DWORD *'
remoting\host\desktop_session_proxy.cc(205): note: Types pointed to are
unrelated; conversion requires reinterpret_cast, C-style cast or function-style
cast

+    PLOG(ERROR) << "ProcessIdToSessionId() failed!";
+  }
+#endif  // defined(OS_WIN)
 }
 
 void DesktopSessionProxy::OnChannelError() {
@@ -253,6 +260,7 @@ void DesktopSessionProxy::DetachFromDesktop() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   desktop_channel_.reset();
+  desktop_session_id_ = UINT32_MAX;
 
   if (desktop_process_.IsValid())
     desktop_process_.Close();