Ensure host_forwarder is killed when setting up/tearing down sharding.

build/android/pylib/forwarder.py

Index: build/android/pylib/forwarder.py
diff --git a/build/android/pylib/forwarder.py b/build/android/pylib/forwarder.py
index 305278f9a3a42b94b10d582cfba128ad57a11aa5..460a3dc97ac0fce75559fb73e13b77a1670b076e 100644
--- a/build/android/pylib/forwarder.py
+++ b/build/android/pylib/forwarder.py
@@ -105,12 +105,16 @@ class Forwarder(object):
 
   @staticmethod
   def KillHost(build_type):
+    logging.info('Killing host_forwarder.')
     host_forwarder_path = _MakeBinaryPath(build_type, 'host_forwarder')
     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
         [host_forwarder_path, 'kill-server'])
     if exit_code != 0:
-      raise Exception('%s exited with %d:\n%s' % (host_forwarder_path,
-                                                  exit_code, '\n'.join(output)))
+      (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
+          ['pkill', 'host_forwarder'])
+      if exit_code != 0:
+        raise Exception('%s exited with %d:\n%s' % (
+              host_forwarder_path, exit_code, '\n'.join(output)))
 
   @staticmethod
   def KillDevice(adb):