Move Python setup/tear down logic into Forwarder itself.

build/android/pylib/instrumentation/test_runner.py

Index: build/android/pylib/instrumentation/test_runner.py
diff --git a/build/android/pylib/instrumentation/test_runner.py b/build/android/pylib/instrumentation/test_runner.py
index a2692faf65e6c1608765fcb6bff815639150b2c0..3015925b0810f1272228952b89abc697d1972055 100644
--- a/build/android/pylib/instrumentation/test_runner.py
+++ b/build/android/pylib/instrumentation/test_runner.py
@@ -153,11 +153,13 @@ class TestRunner(base_test_runner.BaseTestRunner):
     http_server_ports = self.LaunchTestHttpServer(
         os.path.join(constants.DIR_SOURCE_ROOT), self._lighttp_port)
     if self.ports_to_forward:
-      self.StartForwarder([(port, port) for port in self.ports_to_forward])
+      self.ForwardPorts([(port, port) for port in self.ports_to_forward])
     self.flags.AddFlags(['--enable-test-intents'])
 
   def TearDown(self):
     """Cleans up the test harness and saves outstanding data from test run."""
+    if self.ports_to_forward:
+      self._UnmapPortPairs(self.ports_to_forward)
     super(TestRunner, self).TearDown()
 
   def TestSetup(self, test):
@@ -170,9 +172,6 @@ class TestRunner(base_test_runner.BaseTestRunner):
     self._SetupIndividualTestTimeoutScale(test)
     self.tool.SetupEnvironment()
 
-    # Make sure the forwarder is still running.
-    self.RestartHttpServerForwarderIfNecessary()
-
   def _IsPerfTest(self, test):
     """Determines whether a test is a performance test.