[Installer Test] Update chrome_helper.GetProcessIDAndPathPairs() to use psutil.

chrome/test/mini_installer/chrome_helper.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Common helper module for working with Chrome's processes and windows."""
 
-import ctypes
-import pywintypes
+import psutil
 import re
-import win32con
 import win32gui
 import win32process
 
 
 def GetProcessIDAndPathPairs():
   """Returns a list of 2-tuples of (process id, process path).
-
-  This is needed because psutil is not available on Windows slave machines (see:
-  http://crbug.com/257696).
-  TODO(sukolsak): Use psutil.process_iter() once it becomes available.
   """
   process_id_and_path_pairs = []
-  for process_id in win32process.EnumProcesses():
-    process_handle = ctypes.windll.kernel32.OpenProcess(
-        win32con.PROCESS_QUERY_INFORMATION | win32con.PROCESS_VM_READ, False,
-        process_id)
-    if not process_handle:
-      continue
+  for process in psutil.process_iter():
     try:
-      process_path = win32process.GetModuleFileNameEx(process_handle, 0)
-      process_id_and_path_pairs.append((process_id, process_path))
-    except pywintypes.error:
+      process_id_and_path_pairs.append((process.pid, process.exe))
+    except psutil.Error:
       # It's normal that some processes are not accessible.
       pass
   return process_id_and_path_pairs
 
 
 def GetProcessIDs(process_path):
   """Returns a list of IDs of processes whose path is |process_path|.
 
   Args:
     process_path: The path to the process.
@@ skipping 35 matching lines @@
     process_ids: A list of process IDs.
     class_pattern: The regular expression pattern of the window class name.
 
   Returns:
     A boolean indicating whether such window exists.
   """
   for hwnd in GetWindowHandles(process_ids):
     if re.match(class_pattern, win32gui.GetClassName(hwnd)):
       return True
   return False