Support running with mojo:debugger in devtools.

mojo/devtools/common/devtoolslib/linux_shell.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import subprocess
 
 from devtoolslib.shell import Shell
 from devtoolslib import http_server
 
 
@@ skipping 19 matching lines @@
 
     Args:
       local_dir_path: path to the directory to be served
       port: port at which the server will be available to the shell
 
     Returns:
       The url that the shell can use to access the content of |local_dir_path|.
     """
     return 'http://%s:%d/' % http_server.StartHttpServer(local_dir_path, port)
 
+  def ForwardHostPortToShell(self, host_port):
+    """Forwards a port on the host machine to the same port wherever the shell
+    is running.
+
+    This is a no-op if the shell is running locally.
+    """
+    pass
+
   def Run(self, arguments):
     """Runs the shell with given arguments until shell exits, passing the stdout
     mingled with stderr produced by the shell onto the stdout.
 
     Returns:
       Exit code retured by the shell or None if the exit code cannot be
       retrieved.
     """
     command = self.command_prefix + [self.executable_path] + arguments
     return subprocess.call(command, stderr=subprocess.STDOUT)
 
   def RunAndGetOutput(self, arguments):
     """Runs the shell with given arguments until shell exits.
 
     Args:
       arguments: list of arguments for the shell
 
     Returns:
       A tuple of (return_code, output). |return_code| is the exit code returned
       by the shell or None if the exit code cannot be retrieved. |output| is the
       stdout mingled with the stderr produced by the shell.
     """
     command = self.command_prefix + [self.executable_path] + arguments
     p = subprocess.Popen(command, stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT)
     (output, _) = p.communicate()
     return p.returncode, output