Bug 1547730 - do s/StringIO.StringIO/six.StringIO/ to support py3 r=#build

Differential Revision: https://phabricator.services.mozilla.com/D28101

--HG--
extra : rebase_source : 25292a350368f109b22350fedc066f2cd257b697
extra : intermediate-source : 284a97f47d5027b4d24c76f56bb133fea477555f
extra : source : 7e0974046e5680b87e4510df0dc3279be453ef9c

python/mozbuild/mozbuild/base.py

@@ -19,7 +19,6 @@ except ImportError:
     # shutil.which is not available in Python 2.7
     import which
 
-from StringIO import StringIO
 from mach.mixin.process import ProcessExecutionMixin
 from mozversioncontrol import (
     get_repository_from_build_config,
@@ -273,7 +272,7 @@ class MozbuildObject(ProcessExecutionMixin):
         # the environment variable, which has an impact on autodetection (when
         # path is MozconfigLoader.AUTODETECT), and memoization wouldn't account
         # for it without the explicit (unused) argument.
-        out = StringIO()
+        out = six.StringIO()
         env = os.environ
         if path and path != MozconfigLoader.AUTODETECT:
             env = dict(env)

python/mozbuild/mozpack/test/test_files.py

@@ -60,12 +60,12 @@ import mozfile
 import mozunit
 import os
 import random
+import six
 import sys
 import tarfile
 import mozpack.path as mozpath
 from tempfile import mkdtemp
 from io import BytesIO
-from StringIO import StringIO
 
 
 class TestWithTmpDir(unittest.TestCase):
@@ -921,7 +921,7 @@ class TestMinifiedJavaScript(TestWithTmpDir):
 
     def test_minified_verify_failure(self):
         orig_f = GeneratedFile(b'\n'.join(self.orig_lines))
-        errors.out = StringIO()
+        errors.out = six.StringIO()
         min_f = MinifiedJavaScript(orig_f,
                                    verify_command=self._verify_command('1'))