Write mojom and StructTraits for DisplaySnapshot.

ui/display/display_snapshot_mojo.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_DISPLAY_SNAPSHOT_MOJO_H_
+#define UI_DISPLAY_DISPLAY_SNAPSHOT_MOJO_H_
+

[kylechar, 2017/02/15 16:48:45]

Add include for unique_ptr.

#include <memory>

[thanhph, 2017/02/16 11:48:21]

Done.

+#include "base/macros.h"
+#include "ui/display/display_export.h"
+#include "ui/display/types/display_snapshot.h"
+
+namespace display {
+
+// DisplaySnapshot implementation that can be used with Mojo IPC.
+class DISPLAY_EXPORT DisplaySnapshotMojo : public DisplaySnapshot {
+ public:
+  DisplaySnapshotMojo(int64_t display_id,
+                      const gfx::Point& origin,
+                      const gfx::Size& physical_size,
+                      DisplayConnectionType type,
+                      bool is_aspect_preserving_scaling,
+                      bool has_overscan,
+                      bool has_color_correction_matrix,
+                      std::string display_name,
+                      const base::FilePath& sys_path,
+                      int64_t product_id,
+                      DisplayModeList modes,
+                      const std::vector<uint8_t>& edid,
+                      const DisplayMode* current_mode,
+                      const DisplayMode* native_mode,
+                      const gfx::Size& maximum_cursor_size);
+  ~DisplaySnapshotMojo() override;
+  virtual std::unique_ptr<DisplaySnapshotMojo> Clone() const;

[kylechar, 2017/02/15 16:48:45]

Why is this virtual?

[thanhph, 2017/02/16 11:48:20]

Is there other class that will implement DisplaySnapShot? I notice
DisplayMode->Clone() is also virtual.
(http://stackoverflow.com/questions/17842594/virtual-function-inheritance) 

[kylechar, 2017/02/16 14:05:42]

Virtual only works for subclasses. Putting a virtual method in
DisplaySnapshotMojo has no effect on the parent class DisplaySnapshot. You'd
have to be planning on using virtual dispatch in subclasses of
DisplaySnapshotMojo, which AFAIK there will be none?

+
+  // DisplaySnapshot:
+  std::string ToString() const override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DisplaySnapshotMojo);
+};
+
+}  // namespace display
+
+#endif  // UI_DISPLAY_DISPLAY_SNAPSHOT_MOJO_H_