[Telemetry] Ensure we close ippet's handle if anything goes wrong.

tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py

Index: tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py
diff --git a/tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py b/tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py
index 4b33f0b805cc303e53c5b5b0acd8e776e649da52..8f43271332bccfb5f59c625e0d389b2c138fb36b 100644
--- a/tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/ippet_power_monitor.py
@@ -121,26 +121,28 @@ class IppetPowerMonitor(power_monitor.PowerMonitor):
   def StopMonitoringPower(self):
     assert self._ippet_handle, (
         'Called StopMonitoringPower() before StartMonitoringPower().')
-    # Stop IPPET.
-    ippet_quit_url = 'http://127.0.0.1:%d/ippet?cmd=quit' % self._ippet_port
-    quit_output = urllib2.urlopen(ippet_quit_url).read()
-    if quit_output != 'quiting\r\n':
-      raise IppetError('Failed to quit IPPET: %s' % quit_output.strip())
-    wait_return_code = win32event.WaitForSingleObject(self._ippet_handle, 20000)
-    if wait_return_code != win32event.WAIT_OBJECT_0:
-      if wait_return_code == win32event.WAIT_TIMEOUT:
-        raise IppetError('Timed out waiting for IPPET to close.')
-      else:
-        raise IppetError('Error code %d while waiting for IPPET to close.' %
-                        wait_return_code)
-    ippet_exit_code = win32process.GetExitCodeProcess(self._ippet_handle)
-    if ippet_exit_code == win32con.STILL_ACTIVE:
-      raise IppetError('IPPET is still running but should have stopped.')
-    elif ippet_exit_code != 0:
-      raise IppetError('IPPET closed with exit code %d.' % ippet_exit_code)
-    self._ippet_handle.Close()
-    self._ippet_handle = None
-    self._ippet_port = None
+    try:
+      ippet_quit_url = 'http://127.0.0.1:%d/ippet?cmd=quit' % self._ippet_port
+      quit_output = urllib2.urlopen(ippet_quit_url).read()
+      if quit_output != 'quiting\r\n':
+        raise IppetError('Failed to quit IPPET: %s' % quit_output.strip())
+      wait_return_code = win32event.WaitForSingleObject(self._ippet_handle,
+                                                        20000)
+      if wait_return_code != win32event.WAIT_OBJECT_0:
+        if wait_return_code == win32event.WAIT_TIMEOUT:
+          raise IppetError('Timed out waiting for IPPET to close.')
+        else:
+          raise IppetError('Error code %d while waiting for IPPET to close.' %
+                          wait_return_code)
+      ippet_exit_code = win32process.GetExitCodeProcess(self._ippet_handle)
+      if ippet_exit_code == win32con.STILL_ACTIVE:
+        raise IppetError('IPPET is still running but should have stopped.')
+      elif ippet_exit_code != 0:
+        raise IppetError('IPPET closed with exit code %d.' % ippet_exit_code)
+    finally:
+      self._ippet_handle.Close()

[dtu, 2014/08/06 19:04:22]

Closing the handle just releases the reference, it doesn't terminate the
process.
if win32process.GetExitCodeProcess(self._ippet_handle) == win32con.STILL_ACTIVE:
  win32process.TerminateProcess(self._ippet_handle)

+      self._ippet_handle = None
+      self._ippet_port = None
 
     # Read IPPET's log file.
     log_file = os.path.join(self._output_dir, 'ippet_log_processes.xls')