ninja windows: simpler link-wrapper code

pylib/gyp/win_tool.py

 #!/usr/bin/env python
 
 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility functions for Windows builds.
 
 These functions are executed via gyp-win-tool when using the ninja generator.
 """
@@ skipping 40 matching lines @@
       shutil.copy2(source, dest)
 
   def ExecLinkWrapper(self, *args):
     """Filter diagnostic output from link that looks like:
     '   Creating library ui.dll.lib and object ui.dll.exp'
     This happens when there are exports from the dll or exe.
     """
     popen = subprocess.Popen(args,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.STDOUT)
-    out, _ = popen.communicate()
-    for line in out.splitlines():
+    for line in popen.stdout:
       if not line.startswith('   Creating library '):
         sys.stdout.write(line)
     return popen.returncode
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))