mash: improves browser frame decorations

ash/public/interfaces/window_style.mojom

Index: ash/public/interfaces/window_style.mojom
diff --git a/ash/public/interfaces/window_style.mojom b/ash/public/interfaces/window_style.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..819e232cb1fc719df03bea80c43737172650a9b3
--- /dev/null
+++ b/ash/public/interfaces/window_style.mojom
@@ -0,0 +1,13 @@
+// Copyright 2017 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.
+
+module ash.mojom;
+
+// Used to specify how the frame decorations and style should look.
+enum WindowStyle {
+  DEFAULT = 0,
+  BROWSER,
+};
+
+const string kAshWindowStyle_InitProperty = "ash:window-style";