Unicode input is also accepted for stdin.

R=dpranke@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/6878069

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@82410 0039d316-1c4b-4281-b951-d872f2087c98

subprocess2.py

@@ -207,7 +207,7 @@ def communicate(args, timeout=None, **kwargs):
       kwargs['stdin'] = open(os.devnull, 'r')
       stdin = None
     else:
-      assert isinstance(stdin, str)
+      assert isinstance(stdin, basestring)
       # When stdin is passed as an argument, use it as the actual input data and
       # set the Popen() parameter accordingly.
       kwargs['stdin'] = PIPE