Multiple improvements to windows bash integration.

python_runner.sh

 # Copyright 2015 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.
 
 ## This file is designed to be sourced from a bash script whose name takes the
 ## form 'command-name'. This script will then instead invoke
 ## '[depot_tools]/command_name.py' correctly under mingw as well
 ## as posix-ey systems, passing along all other command line flags.
 
 ## Example:
@@ skipping 23 matching lines @@
     # within the depot_tools dir itself). In that case, treat it as if run like:
     # "./command"
     DEPOT_TOOLS="."
     BASENAME="$0"
   else
     BASENAME="${0##*/}"
   fi
 else
   BASENAME="${0##*\\}"
 fi
+
 SCRIPT="${SCRIPT-${BASENAME//-/_}.py}"
 
-if [[ -e "$DEPOT_TOOLS/python.bat" && $OSTYPE = msys ]]; then
-  cmd.exe //c "$DEPOT_TOOLS\\python.bat" "$DEPOT_TOOLS\\$SCRIPT" "$@"
+if [[ $PYTHON_DIRECT = 1 ]]; then 
+  python.exe "$DEPOT_TOOLS\\$SCRIPT" "$@"
 else
-  exec "$DEPOT_TOOLS/$SCRIPT" "$@"
+  if [[ -e "$DEPOT_TOOLS/python.bat" && $OSTYPE = msys ]]; then
+    cmd.exe //c "$DEPOT_TOOLS\\python.bat" "$DEPOT_TOOLS\\$SCRIPT" "$@"
+  else
+    exec "$DEPOT_TOOLS/$SCRIPT" "$@"
+  fi
 fi