Move Python setup/tear down logic into Forwarder itself.

build/android/adb_reverse_forwarder.py

Index: build/android/adb_reverse_forwarder.py
diff --git a/build/android/adb_reverse_forwarder.py b/build/android/adb_reverse_forwarder.py
index e465ea77156795e39f951af21022c3ea9adfd6b7..0ec1db1af347f48116c5743add46ddad9dec1a99 100755
--- a/build/android/adb_reverse_forwarder.py
+++ b/build/android/adb_reverse_forwarder.py
@@ -17,7 +17,6 @@ import time
 
 from pylib import android_commands, forwarder
 from pylib.utils import run_tests_helper
-from pylib.valgrind_tools import CreateTool
 
 
 def main(argv):
@@ -51,17 +50,15 @@ def main(argv):
     sys.exit(1)
 
   adb = android_commands.AndroidCommands(options.device)
-  tool = CreateTool(None, adb)
-  forwarder_instance = forwarder.Forwarder(adb, options.build_type)
   try:
-    forwarder_instance.Run(port_pairs, tool)
+    Forwarder.Map(port_pairs, adb, options.build_type)
     while True:
       time.sleep(60)
   except KeyboardInterrupt:
     sys.exit(0)
   finally:
-    forwarder_instance.Close()
-
+    for (device_port, _) in port_pairs:
+      Forwarder.UnmapDevicePort(device_port, adb)
 
 if __name__ == '__main__':
   main(sys.argv)