Add Xorg+dummy as alternative for Xvfb

remoting/host/curtain_mode_linux.cc

Index: remoting/host/curtain_mode_linux.cc
diff --git a/remoting/host/curtain_mode_linux.cc b/remoting/host/curtain_mode_linux.cc
index 05031bfec1b255b300d521dfde30b5686b785fa0..272fb4bcaba4274108f10892852040a3bd1e3c24 100644
--- a/remoting/host/curtain_mode_linux.cc
+++ b/remoting/host/curtain_mode_linux.cc
@@ -61,6 +61,7 @@ bool CurtainModeLinux::IsXvfbSession() {
   XDeviceInfo* devices;
   bool found_xvfb_mouse = false;
   bool found_xvfb_keyboard = false;
+  bool found_crd_void_input = false;
   bool found_other_devices = false;
   devices = XListInputDevices(display, &num_devices);
   for (int i = 0; i < num_devices; i++) {
@@ -68,6 +69,9 @@ bool CurtainModeLinux::IsXvfbSession() {
     if (device_info->use == IsXExtensionPointer) {
       if (strcmp(device_info->name, "Xvfb mouse") == 0) {
         found_xvfb_mouse = true;
+      } else if (strcmp(device_info->name,
+                        "Chrome Remote Desktop Input") == 0) {
+        found_crd_void_input = true;
       } else if (strcmp(device_info->name, "Virtual core XTEST pointer") != 0) {
         found_other_devices = true;
         HOST_LOG << "Non Xvfb mouse found: " << device_info->name;
@@ -97,7 +101,8 @@ bool CurtainModeLinux::IsXvfbSession() {
   }
   XFreeDeviceList(devices);
   XCloseDisplay(display);
-  return found_xvfb_mouse && found_xvfb_keyboard && !found_other_devices;
+  return (found_xvfb_mouse && found_xvfb_keyboard) != found_crd_void_input

[Jamie, 2016/05/07 00:05:47]

Why are you using != here instead of ||? It makes the code harder to read, and I
don't think we care if we find both.

[rkjnsn, 2016/05/09 16:58:33]

My initial thought was that it should be xor since we'll either be running on
one or the other, but I agree it shouldn't be a problem to use ||, so I'll
switch if you think it's more readable that way.

[Jamie, 2016/05/09 17:08:43]

Xor is unusual enough that it's not immediately clear that "!=" is the
non-bitwise form of "^", which is mostly what makes this hard to read.  I think
"^" would work, and would be clearer, but I think "||" is better.

+      && !found_other_devices;
 }
 
 // static