Add systemwide session file for Chromoting

remoting/host/linux/linux_me2me_host.py

Index: remoting/host/linux/linux_me2me_host.py
diff --git a/remoting/host/linux/linux_me2me_host.py b/remoting/host/linux/linux_me2me_host.py
index 42a954704952b34c702289ae7ea15434083bcaee..24fec1815f9a0173c4f1d33b35606d54ab5da1dd 100755
--- a/remoting/host/linux/linux_me2me_host.py
+++ b/remoting/host/linux/linux_me2me_host.py
@@ -56,6 +56,7 @@ CHROME_REMOTING_GROUP_NAME = "chrome-remote-desktop"
 HOME_DIR = os.environ["HOME"]
 CONFIG_DIR = os.path.join(HOME_DIR, ".config/chrome-remote-desktop")
 SESSION_FILE_PATH = os.path.join(HOME_DIR, ".chrome-remote-desktop-session")
+SYSTEM_SESSION_FILE_PATH = "/etc/chrome-remote-desktop-session"
 
 X_LOCK_FILE_TEMPLATE = "/tmp/.X%d-lock"
 FIRST_X_DISPLAY_NUMBER = 20
@@ -530,14 +531,9 @@ def choose_x_session():
     the first parameter of subprocess.Popen().  If a suitable session cannot
     be found, returns None.
   """
-  # If the session wrapper script (see below) is given a specific session as an
-  # argument (such as ubuntu-2d on Ubuntu 12.04), the wrapper will run that
-  # session instead of looking for custom .xsession files in the home directory.

[Lambros, 2014/04/24 20:27:52]

Don't think this comment makes much sense any more. Modern display-managers
don't check .xsession, so we shouldn't do it either.

-  # So it's necessary to test for these files here.
   XSESSION_FILES = [
     SESSION_FILE_PATH,
-    "~/.xsession",
-    "~/.Xsession" ]
+    SYSTEM_SESSION_FILE_PATH ]
   for startup_file in XSESSION_FILES:
     startup_file = os.path.expanduser(startup_file)
     if os.path.exists(startup_file):