Remove DisplayStructTraitsTest interface.

ui/display/mojo/display_snapshot_mojo_struct_traits.h

 // 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.
 
 #ifndef UI_DISPLAY_MOJO_DISPLAY_SNAPSHOT_MOJO_STRUCT_TRAITS_H_
 #define UI_DISPLAY_MOJO_DISPLAY_SNAPSHOT_MOJO_STRUCT_TRAITS_H_
 
+#include "ipc/ipc_message_utils.h"

[yzshen1, 2017/05/03 16:39:46]

I thought keeping these includes in the .cc file should work. Have I missed
anything?

[kylechar, 2017/05/03 17:18:55]

There are errors in the display_unittests target looking for templates without
these changes.

If I undo the changes to display_snapshot_mojo_struct_straits.h/cc and
display_struct_traits.h/cc then I get the following compile errors:

../../mojo/public/cpp/bindings/lib/template_util.h:74:30: error: implicit
instantiation of undefined template
'mojo::StructTraits<gfx::mojom::RectDataView, gfx::Rect>'

../../mojo/public/cpp/bindings/lib/native_struct_serialization.h:36:13: error:
no member named 'GetSize' in 'IPC::ParamTraits<base::FilePath>'

gen/ui/display/mojo/display_constants.mojom-shared.h:142:36: error: implicit
instantiation of undefined template
'mojo::EnumTraits<display::mojom::DisplayConnectionType,
display::DisplayConnectionType>'

Plus lots of other related errors.

[yzshen1, 2017/05/03 17:22:03]

Ah, right. Because the serialization is done outside of the .cc file
(deserialization should be fine because it uses the StructTraits::Read which is
implemented in the cc file). Thanks for explanation!

+#include "ui/display/mojo/display_constants_struct_traits.h"
+#include "ui/display/mojo/display_mode_struct_traits.h"
 #include "ui/display/mojo/display_snapshot_mojo.mojom.h"
 #include "ui/display/types/display_mode.h"
 #include "ui/display/types/display_snapshot_mojo.h"
+#include "ui/gfx/geometry/mojo/geometry_struct_traits.h"
 
 namespace mojo {
 
 template <>
 struct StructTraits<display::mojom::DisplaySnapshotMojoDataView,
                     std::unique_ptr<display::DisplaySnapshotMojo>> {
   static int64_t display_id(
       const std::unique_ptr<display::DisplaySnapshotMojo>& snapshot) {
     return snapshot->display_id();
   }
@@ skipping 72 matching lines @@
     return snapshot->maximum_cursor_size();
   }
 
   static bool Read(display::mojom::DisplaySnapshotMojoDataView data,
                    std::unique_ptr<display::DisplaySnapshotMojo>* out);
 };
 
 }  // namespace mojo
 
 #endif  // UI_DISPLAY_MOJO_DISPLAY_SNAPSHOT_MOJO_STRUCT_TRAITS_H_