Write mojom and StructTraits for DisplaySnapshot.

ui/display/mojo/display_snapshot_mojo.typemap

Index: ui/display/mojo/display_snapshot_mojo.typemap
diff --git a/ui/display/mojo/display_snapshot_mojo.typemap b/ui/display/mojo/display_snapshot_mojo.typemap
new file mode 100644
index 0000000000000000000000000000000000000000..5a831be6299290343ced1d000ad869a040cee028
--- /dev/null
+++ b/ui/display/mojo/display_snapshot_mojo.typemap
@@ -0,0 +1,17 @@
+# 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.
+
+mojom = "//ui/display/mojo/display_snapshot_mojo.mojom"
+public_headers = [ "//ui/display/display_snapshot_mojo.h" ]
+traits_headers = [ "//ui/display/mojo/display_snapshot_mojo_struct_traits.h" ]
+sources = [
+  "//ui/display/mojo/display_snapshot_mojo_struct_traits.cc",
+]
+public_deps = [
+  "//ui/display",
+]
+deps = [
+  "//ui/gfx/geometry",
+]
+type_mappings = [ "display.mojom.DisplaySnapshotMojo=std::unique_ptr<display::DisplaySnapshotMojo>[move_only]" ]