devtools: new workflow for multiple simultaneous `mojo_run` runs.

mojo/devtools/common/devtoolslib/android_shell.py

 # Copyright 2014 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 atexit
 import hashlib
 import logging
 import os
 import os.path
 import random
 import re
 import subprocess
 import sys
 import tempfile
 import threading
 import time
 import uuid
 
-from devtoolslib.http_server import start_http_server
+from devtoolslib import http_server
 from devtoolslib.shell import Shell
 from devtoolslib.utils import overrides
 
 
 # Tags used by mojo shell Java logging.
 _LOGCAT_JAVA_TAGS = [
     'AndroidHandler',
     'MojoFileHelper',
     'MojoMain',
     'MojoShellActivity',
@@ skipping 384 matching lines @@
           host_port = self._forward_host_port_to_device(0, device_port)
           print ("Dart observatory available at the host at http://127.0.0.1:%d"
                  % host_port)
 
     logcat_watch_thread = threading.Thread(
         target=_forward_observatories_as_needed)
     logcat_watch_thread.daemon = True
     logcat_watch_thread.start()
 
   @overrides(Shell)
-  def serve_local_directories(self, mappings, port=0, free_host_port=False):
+  def serve_local_directories(self, mappings, port=0, reuse_servers=False):
     assert mappings
-    host_port = 0 if free_host_port else port
-    server_address = start_http_server(mappings, host_port=host_port)
+    if reuse_servers:
+      assert port, 'Cannot reuse the server when |port| is 0.'
+      server_address = ('127.0.0.1', port)
+    else:
+      server_address = http_server.start_http_server(mappings, port)
 
     return 'http://127.0.0.1:%d/' % self._forward_device_port_to_host(
         port, server_address[1])
 
   @overrides(Shell)
   def forward_host_port_to_shell(self, host_port):
     self._forward_host_port_to_device(host_port, host_port)
 
   @overrides(Shell)
   def run(self, arguments):
@@ skipping 23 matching lines @@
           Results.output = rf.read()
 
     run_thread = threading.Thread(target=do_run)
     run_thread.start()
     run_thread.join(timeout)
 
     if run_thread.is_alive():
       self.stop_shell()
       return None, Results.output, True
     return None, Results.output, False