Better defaulting of attributes
diff --git a/templates/tools/run_tests/tests.json.template b/templates/tools/run_tests/tests.json.template
index 113eebe..337858d 100644
--- a/templates/tools/run_tests/tests.json.template
+++ b/templates/tools/run_tests/tests.json.template
@@ -4,8 +4,8 @@
 
 ${json.dumps([{"name": tgt.name,
                "language": tgt.language,
-	       "platforms": tgt.get("platforms", ["windows", "posix"]),
-               "flaky": tgt.get("flaky", False)}
+	       "platforms": tgt.platforms,
+               "flaky": tgt.flaky}
               for tgt in targets
               if tgt.get('run', True) and tgt.build == 'test'],
              sort_keys=True, indent=2)}
diff --git a/tools/buildgen/plugins/expand_bin_attrs.py b/tools/buildgen/plugins/expand_bin_attrs.py
new file mode 100755
index 0000000..0896a5a
--- /dev/null
+++ b/tools/buildgen/plugins/expand_bin_attrs.py
@@ -0,0 +1,51 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Buildgen expand binary attributes plugin.
+
+This fills in any optional attributes.
+
+"""
+
+
+def mako_plugin(dictionary):
+  """The exported plugin code for expand_filegroups.
+
+  The list of libs in the build.json file can contain "filegroups" tags.
+  These refer to the filegroups in the root object. We will expand and
+  merge filegroups on the src, headers and public_headers properties.
+
+  """
+
+  targets = dictionary.get('targets')
+
+  for tgt in targets:
+    tgt['flaky'] = tgt.get('flaky', False)
+    tgt['platforms'] = tgt.get('platforms', ['windows', 'posix'])
+