add unittest for render_pictures binary

tools/test_pictures.py

 '''
+Copyright 2012 Google Inc.
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+
 Compares the rendererings of serialized SkPictures to expected images.
 
 Launch with --help to see more information.
 
-
-Copyright 2012 Google Inc.
-
-Use of this source code is governed by a BSD-style license that can be
-found in the LICENSE file.
+TODO(epoger): Combine with overlapping tools/tests/render_pictures_test.py .
+See https://code.google.com/p/skia/issues/detail?id=1943#c2
 '''
 # common Python modules
 import os
 import optparse
 import sys
 import shutil
 import tempfile
 
 # modules declared within this same directory
 import test_rendering
@@ skipping 67 matching lines @@
 
     if (options.device is not None):
         extra_args += ' --device %s' % options.device
 
     test_rendering.TestRenderSkps(inputs, expected_dir, options.render_dir,
                                   options.diff_dir, 'render_pictures',
                                   extra_args)
 
 if __name__ == '__main__':
     Main(sys.argv)