Pass correct --parent-window value to native messaging hosts

chrome/test/data/native_messaging/native_hosts/echo.py

Index: chrome/test/data/native_messaging/native_hosts/echo.py
diff --git a/chrome/test/data/native_messaging/native_hosts/echo.py b/chrome/test/data/native_messaging/native_hosts/echo.py
index e9550f6cf678f7831b2617c03b3e39f23a6f7dfe..b7176b141ac617931cc6c7b3d9cac44ff87fcaad 100755
--- a/chrome/test/data/native_messaging/native_hosts/echo.py
+++ b/chrome/test/data/native_messaging/native_hosts/echo.py
@@ -7,6 +7,7 @@
 # All this client does is echo the text it receives back at the extension.
 
 import os
+import platform
 import sys
 import struct
 
@@ -22,13 +23,24 @@ def WriteMessage(message):
 def Main():
   message_number = 0
 
+  caller_url = None;

[miket_OOO, 2014/01/07 17:15:11]

Begone, semicolon!

[Sergey Ulanov, 2014/01/07 20:56:10]

Done.

+  parent_window = None
+
   if len(sys.argv) < 2:
     sys.stderr.write("URL of the calling application is not specified.\n")
-    return;
+    return 1
   for arg in sys.argv[1:]:
-    if not arg.startswith('--'):
+    if arg.startswith('--'):
+      if arg.startswith('--parent-window='):

[miket_OOO, 2014/01/07 17:15:11]

Not a big deal, but it makes me sad when I see manual parsing of command-line
arguments when wonderful libraries like
http://docs.python.org/2/library/argparse.html#module-argparse exist. OK to keep
as-is -- or maybe add a TODO for next time?

[Sergey Ulanov, 2014/01/07 20:56:10]

Added TODO. FWIW argparse is available only starting Python 2.7 and we are still
using 2.6 on Windows. This script could use optparse (which is available in 2.6,
deprecated in 2.7), but it doesn't seem to worth spending time on it right now
given that we would want to switch to argparse in the future.

+        parent_window = long(arg[len('--parent-window='):])
+    elif caller_url == None:
       caller_url = arg
-      break
+
+  if platform.system() == 'Windows':
+    import win32gui
+    if not win32gui.IsWindow(parent_window):
+      sys.stderr.write('Invalid --parent-window.\n')
+      return 1
 
   while 1:
     # Read the message type (first 4 bytes).
@@ -63,10 +75,10 @@ def Main():
 
     message_number += 1
 
-    if not WriteMessage(
-        '{{"id": {0}, "echo": {1}, "caller_url": "{2}"}}'.format(
-          message_number, text, caller_url).encode('utf-8')):
+    message = '{{"id": {0}, "echo": {1}, "caller_url": "{2}"}}'.format(
+          message_number, text, caller_url).encode('utf-8')
+    if not WriteMessage(message):
       break
 
 if __name__ == '__main__':
-  Main()
+  sys.exit(Main())