Prevent creation of the GnubbyExtension if no socket name is defined.

remoting/host/remoting_me2me_host.cc

Index: remoting/host/remoting_me2me_host.cc
diff --git a/remoting/host/remoting_me2me_host.cc b/remoting/host/remoting_me2me_host.cc
index 788968be2ae1b10a87b9ff3d911a4ecf63a522fa..dd35409a255a6bf48a205439341dbdcb4551bc26 100644
--- a/remoting/host/remoting_me2me_host.cc
+++ b/remoting/host/remoting_me2me_host.cc
@@ -427,7 +427,8 @@ class HostProcess : public ConfigWatcher::Delegate,
 
   bool curtain_required_;
   ThirdPartyAuthConfig third_party_auth_config_;
-  bool enable_gnubby_auth_;
+  bool gnubby_auth_policy_enabled_;
+  bool skip_gnubby_extension_creation_;

[Lambros, 2016/02/18 01:02:39]

Optional: Maybe better to invert the meaning and call it
enable_gnubby_extension_ ? Default-initialize to false and set it to true when
the socket name is provided?

[joedow, 2016/02/18 02:24:37]

That's a good point, I was originally thinking I would create the extension for
the other OS's but that doesn't work at this point so I've flipped the flag and
we now only create the extension on Linux and only if the socket name has been
passed in to us.

 
   // Boolean to change flow, where necessary, if we're
   // capturing a window instead of the entire desktop.
@@ -491,7 +492,8 @@ HostProcess::HostProcess(scoped_ptr<ChromotingHostContext> context,
       allow_relay_(true),
       allow_pairing_(true),
       curtain_required_(false),
-      enable_gnubby_auth_(false),
+      gnubby_auth_policy_enabled_(false),
+      skip_gnubby_extension_creation_(false),
       enable_window_capture_(false),
       window_id_(0),
       self_(this),
@@ -886,8 +888,12 @@ void HostProcess::StartOnUiThread() {
 
   base::FilePath gnubby_socket_name = base::CommandLine::ForCurrentProcess()->
       GetSwitchValuePath(kAuthSocknameSwitchName);
-  if (!gnubby_socket_name.empty())
+  if (!gnubby_socket_name.empty()) {
     remoting::GnubbyAuthHandler::SetGnubbySocketName(gnubby_socket_name);
+  } else {
+    // No socket name means no gnubby support.
+    skip_gnubby_extension_creation_ = true;
+  }
 #endif  // defined(OS_LINUX)
 
   // Create a desktop environment factory appropriate to the build type &
@@ -1395,11 +1401,11 @@ bool HostProcess::OnGnubbyAuthPolicyUpdate(base::DictionaryValue* policies) {
   DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
 
   if (!policies->GetBoolean(policy::key::kRemoteAccessHostAllowGnubbyAuth,
-                            &enable_gnubby_auth_)) {
+                            &gnubby_auth_policy_enabled_)) {
     return false;
   }
 
-  if (enable_gnubby_auth_) {
+  if (gnubby_auth_policy_enabled_) {
     HOST_LOG << "Policy enables gnubby auth.";
   } else {
     HOST_LOG << "Policy disables gnubby auth.";
@@ -1536,7 +1542,7 @@ void HostProcess::StartHost() {
                                  context_->audio_task_runner(),
                                  context_->video_encode_task_runner()));
 
-  if (enable_gnubby_auth_) {
+  if (gnubby_auth_policy_enabled_ && !skip_gnubby_extension_creation_) {
     host_->AddExtension(make_scoped_ptr(new GnubbyExtension()));
   }