Include PowerShell in Windows PATH, if available.

slave/run_slave.py

Index: slave/run_slave.py
diff --git a/slave/run_slave.py b/slave/run_slave.py
index 72c5021ec502f20334d466093b1d046b363e5c9a..765528f828724b2e69928698864b496fe3fa3895 100755
--- a/slave/run_slave.py
+++ b/slave/run_slave.py
@@ -57,7 +57,7 @@ def IssueReboot():
                               'for %s' % sys.platform)
 
 
-def SigTerm(*args):
+def SigTerm(*_args):
   """Receive a SIGTERM and do nothing."""
   Log('SigTerm: Received SIGTERM, doing nothing.')
 
@@ -433,8 +433,15 @@ def main():
   os.environ['CHROME_HEADLESS'] = '1'
   os.environ['PAGER'] = 'cat'
 
-  # Platform-specific initialization.
+  # Get the current PATH.
+  path_elements = os.environ['PATH'].split(os.pathsep)
+  def get_path_element(phrase):

[hinoka, 2016/06/23 22:17:55]

This function does something pretty unexpected (to me) so i'd opt for commenting
it

# returns a path element where one or more of it's directories contains the
given phrase.

[dnj (Google), 2016/06/24 03:24:51]

Done.

+    for e in path_elements:
+      if phrase in e:

[Ryan Tseng, 2016/06/23 16:45:30]

if phrase in e.listdir()?

[dnj (Google), 2016/06/24 03:24:51]

"e" is a string here.

+        return [e]
+    return []
 
+  # Platform-specific initialization.
   if sys.platform.startswith('win'):
     # list of all variables that we want to keep
     env_var = [
@@ -484,7 +491,8 @@ def main():
 
     remove_all_vars_except(os.environ, env_var)
 
-    # Extend the env variables with the chrome-specific settings.
+    # Extend the env variables with the chrome-specific settings. Tailor the
+    # slave process' (and derivative tasks') PATH environment variable.
     slave_path = [
         depot_tools,
         # Reuse the python executable used to start this script.
@@ -497,6 +505,10 @@ def main():
         # TODO(hinoka): Remove this when its no longer needed crbug.com/481695
         os.path.join(os.environ['SYSTEMDRIVE'], os.sep, 'cmake', 'bin'),
     ]
+
+    # Include Windows PowerShell in PATH, if defined.

[hinoka, 2016/06/23 22:17:55]

# It does so by searching for a path entry that contains "WindowsPowerShell",
# which is assumed to be the path entry to contain the powershell executable.

[dnj (Google), 2016/06/24 03:24:51]

Done.

+    slave_path += get_path_element('WindowsPowerShell')
+
     # build_internal/tools contains tools we can't redistribute.
     tools = os.path.join(ROOT_DIR, 'build_internal', 'tools')
     if os.path.isdir(tools):