On Windows, fail if there are missing files specified in the project.

gyp_skia

 #!/usr/bin/python
 
 # Copyright 2011 The Android Open Source Project
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script is a wrapper which invokes gyp with the correct --depth argument,
 # and supports the automatic regeneration of build files if all.gyp is
 # changed (Linux-only).
@@ skipping 108 matching lines @@
 
   # Tell gyp to write the build files into output_dir.
   args.extend(['--generator-output', os.path.abspath(get_output_dir())])
 
   # Tell ninja to write its output into the same directory.
   args.extend(['-Goutput_dir=.'])
 
   # By default, we build 'most' instead of 'all' or 'everything'. See skia.gyp.
   args.extend(['-Gdefault_target=most'])
 
+  # Fail if there are files specified in the project but are missing

[epoger, 2014/06/04 15:25:42]

maybe...

# Fail if any files specified in the project are missing

[jvanverth1, 2014/06/04 17:07:14]

Done.

+  if sys.platform.startswith('win'):
+    os.environ['GYP_GENERATOR_FLAGS'] = 'msvs_error_on_missing_sources=1'

[epoger, 2014/06/04 15:25:42]

Is it possible for the user to have already specified some GYP_GENERATOR_FLAGS? 
Maybe we need to *append* to it instead of replacing it?

[jvanverth1, 2014/06/04 17:07:14]

Done.

+
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   if '--dry-run' in args:
     args.remove('--dry-run')
     print gyp_source_dir, ' '.join(args)
   else:
     # Off we go...
     sys.exit(gyp.main(args))