Forward the fixed flutter observatory port in `android_shell.py`.

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
@@ skipping 16 matching lines @@
     'MojoFileHelper',
     'MojoShellApplication',
     'ShellService',
 ]
 
 _MOJO_SHELL_PACKAGE_NAME = 'org.chromium.mojo.shell'
 
 # Used to parse the output of `adb devices`.
 _ADB_DEVICES_HEADER = 'List of devices attached'
 
+# Fixed port on which Flutter observatory is run.
+_FLUTTER_OBSERVATORY_PORT = 8181
+
 
 _logger = logging.getLogger()
 
 
 def _exit_if_needed(process):
   """Exits |process| if it is still alive."""
   if process.poll() is None:
     process.kill()
 
 
@@ skipping 344 matching lines @@
           device_port = int(match.group(1))
           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()
 
+  def forward_flutter_observatory_port(self):
+    """Forwards the fixed port on which Flutter observatory is run."""
+    self._forward_host_port_to_device(_FLUTTER_OBSERVATORY_PORT,
+                                      _FLUTTER_OBSERVATORY_PORT)
+
   @overrides(Shell)
   def serve_local_directories(self, mappings, port, reuse_servers=False):
     assert mappings
     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):
     self.clean_logs()
     self.forward_observatory_ports()
+    self.forward_flutter_observatory_port()
 
     p = self.show_logs()
     self.start_shell(arguments, sys.stdout, p.terminate)
     p.wait()
     return None
 
   @overrides(Shell)
   def run_and_get_output(self, arguments, timeout=None):
     class Results:
       """Workaround for Python scoping rules that prevent assigning to variables
       from the outer scope.
       """
       output = None
 
     def do_run():
       (r, w) = os.pipe()
       with os.fdopen(r, 'r') as rf:
         with os.fdopen(w, 'w') as wf:
           self.start_shell(arguments, wf, wf.close)
           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