More Windows build fixes, some tidying in mojo_main

PRESUBMIT.py

 # Copyright (c) 2012 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
@@ skipping 426 matching lines @@
     relative_out_dir = input_api.os_path.relpath(out_dir, temp_parent)
     try:
       input_api.subprocess.check_output(['gn', 'gen', relative_out_dir])
     except input_api.subprocess.CalledProcessError, error:
       return [output_api.PresubmitError(
           'gn gen must not fail.', long_text=error.output)]
 
     # TODO(eseidel): Currently only these are known to pass,
     # once everything passes we can just call 'gn check' once without a filter!
     KNOWN_PASSING = [
-      '//sky/*',
       '//mojo/public/*',
     ]
+    if input_api.platform != 'win32':
+      KNOWN_PASSING += [
+        '//sky/*',
+      ]
     for target_filter in KNOWN_PASSING:
       try:
         input_api.subprocess.check_output(['gn', 'check', relative_out_dir,
             target_filter])
       except input_api.subprocess.CalledProcessError, error:
         error_title = 'gn check %s must not fail.' % target_filter
         return [output_api.PresubmitError(error_title, long_text=error.output)]
   return []
 
 
@@ skipping 1284 matching lines @@
     builders.extend(['cros_x86'])
 
   # The AOSP bot doesn't build the chrome/ layer, so ignore any changes to it
   # unless they're .gyp(i) files as changes to those files can break the gyp
   # step on that bot.
   if (not all(re.search('^chrome', f) for f in files) or
       any(re.search('\.gypi?$', f) for f in files)):
     builders.extend(['android_aosp'])
 
   return GetDefaultTryConfigs(builders)