Support mapping multiple local paths under the same url prefix.

mojo/devtools/common/devtoolslib/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.
 
 
 class Shell(object):
   """Represents an abstract Mojo shell."""
 
   def serve_local_directory(self, local_dir_path, port=0):
     """Serves the content of the local (host) directory, making it available to
@@ skipping 12 matching lines @@
     raise NotImplementedError()
 
   def serve_local_directories(self, mappings, port=0):
     """Serves the content of the local (host) directories, making it available
     to the shell under the url returned by the function.
 
     The server will run on a separate thread until the program terminates. The
     call returns immediately.
 
     Args:
-      mappings: List of tuples (prefix, local_base_path) mapping URLs that start
-          with |prefix| to local directory at |local_base_path|. The prefixes
-          should skip the leading slash. The first matching prefix will be used
-          each time.
+      mappings: List of tuples (prefix, local_base_path_list) mapping URLs that
+          start with |prefix| to one or more local directories enumerated in
+          |local_base_path_list|. The prefixes should skip the leading slash.
+          The first matching prefix and the first location that contains the
+          requested file will be used each time.
       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|.
+      The url that the shell can use to access the server.
     """
     raise NotImplementedError()
 
   def forward_host_port_to_shell(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.
     """
     raise NotImplementedError()
@@ skipping 18 matching lines @@
           terminated
 
     Returns:
       A tuple of (return_code, output, did_time_out). |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.
       |did_time_out| is True iff the shell was terminated because it exceeded
       the |timeout| and False otherwise.
     """
     raise NotImplementedError()