Add the basic infrastructure for the Behavior feature type: BehaviorFeature and

extensions/common/features/behavior_feature.cc

Index: extensions/common/features/behavior_feature.cc
diff --git a/extensions/common/features/behavior_feature.cc b/extensions/common/features/behavior_feature.cc
new file mode 100644
index 0000000000000000000000000000000000000000..15b93f0c1f960d064d97660c3354aeae723ef3ce
--- /dev/null
+++ b/extensions/common/features/behavior_feature.cc
@@ -0,0 +1,12 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/common/features/behavior_feature.h"
+
+namespace extensions {
+
+const char* BehaviorFeature::kWhitelistedForIncognito =
+    "whitelisted_for_incognito";
+
+}  // namespace extensions