Use a single Python Forwarder instance for each base test runner instance.

build/android/pylib/chrome_test_server_spawner.py

Index: build/android/pylib/chrome_test_server_spawner.py
diff --git a/build/android/pylib/chrome_test_server_spawner.py b/build/android/pylib/chrome_test_server_spawner.py
index 2a0fa4641ceaeed81f081196f35a53c7e11f5eff..ec101803ccef57a4b5c7a4acd27ea839a145ba5a 100644
--- a/build/android/pylib/chrome_test_server_spawner.py
+++ b/build/android/pylib/chrome_test_server_spawner.py
@@ -21,7 +21,6 @@ import time
 import urlparse
 
 import constants
-from forwarder import Forwarder
 import ports
 
 
@@ -99,7 +98,7 @@ def _GetServerTypeCommandLine(server_type):
 class TestServerThread(threading.Thread):
   """A thread to run the test server in a separate process."""
 
-  def __init__(self, ready_event, arguments, adb, tool, build_type):
+  def __init__(self, ready_event, arguments, adb, tool, forwarder, build_type):
     """Initialize TestServerThread with the following argument.
 
     Args:
@@ -107,6 +106,7 @@ class TestServerThread(threading.Thread):
       arguments: dictionary of arguments to run the test server.
       adb: instance of AndroidCommands.
       tool: instance of runtime error detection tool.
+      forwarder: instance of Forwarder.
       build_type: 'Release' or 'Debug'.
     """
     threading.Thread.__init__(self)
@@ -121,7 +121,7 @@ class TestServerThread(threading.Thread):
     self.is_ready = False
     self.host_port = self.arguments['port']
     assert isinstance(self.host_port, int)
-    self._test_server_forwarder = None
+    self._test_server_forwarder = forwarder
     # The forwarder device port now is dynamically allocated.
     self.forwarder_device_port = 0
     # Anonymous pipe in order to get port info from test server.
@@ -239,7 +239,6 @@ class TestServerThread(threading.Thread):
       else:
         self.is_ready = _CheckPortStatus(self.host_port, True)
     if self.is_ready:
-      self._test_server_forwarder = Forwarder(self.adb, self.build_type)
       self._test_server_forwarder.Run(
           [(0, self.host_port)], self.tool, '127.0.0.1')
       # Check whether the forwarder is ready on the device.
@@ -255,8 +254,7 @@ class TestServerThread(threading.Thread):
     _WaitUntil(lambda: self.stop_flag, max_attempts=sys.maxint)
     if self.process.poll() is None:
       self.process.kill()
-    if self._test_server_forwarder:
-      self._test_server_forwarder.UnmapDevicePort(self.forwarder_device_port)
+    self._test_server_forwarder.UnmapDevicePort(self.forwarder_device_port)
     self.process = None
     self.is_ready = False
     if self.pipe_out:
@@ -326,6 +324,7 @@ class SpawningServerRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
         json.loads(test_server_argument_json),
         self.server.adb,
         self.server.tool,
+        self.server.forwarder,
         self.server.build_type)
     self.server.test_server_instance.setDaemon(True)
     self.server.test_server_instance.start()
@@ -393,13 +392,14 @@ class SpawningServerRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
 class SpawningServer(object):
   """The class used to start/stop a http server."""
 
-  def __init__(self, test_server_spawner_port, adb, tool, build_type):
+  def __init__(self, test_server_spawner_port, adb, tool, forwarder,
+               build_type):
     logging.info('Creating new spawner on port: %d.', test_server_spawner_port)
     self.server = BaseHTTPServer.HTTPServer(('', test_server_spawner_port),
                                             SpawningServerRequestHandler)
-    self.port = test_server_spawner_port
     self.server.adb = adb
     self.server.tool = tool
+    self.server.forwarder = forwarder
     self.server.test_server_instance = None
     self.server.build_type = build_type