Add IPC messages and structs for passing draggable regions.

common/draggable_region.cc

@@ -0,0 +1,13 @@
+// Copyright (c) 2012 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 "common/draggable_region.h"
+
+namespace atom {
+
+DraggableRegion::DraggableRegion()
+    : draggable(false) {
+}
+
+}  // namespace atom