Bug 1240610 - Align socket_timeout with Python's socket interface; r=automatedtester

When socket.settimeout(None) is set in Python's standard library this
is meant to be equivalent to disabling timeouts on socket operations.
marionette.transport should respect this.

This change set unbreaks the use of the --jdebugger flag to `./mach
marionette-test'.

--HG--
extra : rebase_source : a2b72fd1e40142cbae5387193ea828348c8eee5c

testing/marionette/transport/marionette_transport/transport.py

@@ -116,6 +116,10 @@ class TcpTransport(object):
     connection_lost_msg = "Connection to Marionette server is lost. Check gecko.log (desktop firefox) or logcat (b2g) for errors."
 
     def __init__(self, addr, port, socket_timeout=360.0):
+        """If `socket_timeout` is `0` or `0.0`, non-blocking socket mode
+        will be used.  Setting it to `1` or `None` disables timeouts on
+        socket operations altogether.
+        """
         self.addr = addr
         self.port = port
         self.socket_timeout = socket_timeout
@@ -164,7 +168,7 @@ class TcpTransport(object):
         data = ""
         bytes_to_recv = 10
 
-        while time.time() - now < self.socket_timeout:
+        while self.socket_timeout is None or (time.time() - now < self.socket_timeout):
             try:
                 chunk = self.sock.recv(bytes_to_recv)
                 data += chunk