Write mojom and StructTraits for DisplaySnapshot.

ui/display/mojo/display_constants.mojom

Index: ui/display/mojo/display_constants.mojom
diff --git a/ui/display/mojo/display_constants.mojom b/ui/display/mojo/display_constants.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..576d3e5170612f942c5e6321bc3b77466c50c2f1
--- /dev/null
+++ b/ui/display/mojo/display_constants.mojom
@@ -0,0 +1,21 @@
+// 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 display.mojom;
+
+// Video output types.

[kylechar, 2017/02/09 15:05:53]

Say what non-mojom enum type this corresponds to.

[thanhph1, 2017/02/10 19:54:31]

Done, I put a comment in.

+enum DisplayConnectionType {
+  DISPLAY_CONNECTION_TYPE_NONE = 0,
+  DISPLAY_CONNECTION_TYPE_UNKNOWN = 1,
+  DISPLAY_CONNECTION_TYPE_INTERNAL = 2,
+  DISPLAY_CONNECTION_TYPE_VGA = 4,
+  DISPLAY_CONNECTION_TYPE_HDMI = 8,
+  DISPLAY_CONNECTION_TYPE_DVI = 16,
+  DISPLAY_CONNECTION_TYPE_DISPLAYPORT = 32,
+  DISPLAY_CONNECTION_TYPE_NETWORK = 64,
+  DISPLAY_CONNECTION_TYPE_VIRTUAL = 128,
+
+  // Update this when adding a new type.
+  DISPLAY_CONNECTION_TYPE_LAST = DISPLAY_CONNECTION_TYPE_VIRTUAL

[kylechar, 2017/02/09 15:05:53]

This isn't necessary/wanted here. This type is only used as a wire format, so
you're not going to comparing things against
display::mojom::DISPLAY_CONNECTION_TYPE_LAST.

[thanhph1, 2017/02/10 19:54:31]

Done.

+};