Write mojom and StructTraits for DisplaySnapshot.

ui/display/types/display_mode.h

 // Copyright 2014 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_TYPES_DISPLAY_MODE_H_
 #define UI_DISPLAY_TYPES_DISPLAY_MODE_H_
 
 #include <memory>
 #include <ostream>
 #include <string>
 
 #include "base/macros.h"
 #include "ui/display/types/display_types_export.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace display {
 
 // This class represents the basic information for a native mode. Platforms will
 // extend this class to add platform specific information about the mode.
 class DISPLAY_TYPES_EXPORT DisplayMode {
  public:
   DisplayMode(const gfx::Size& size, bool interlaced, float refresh_rate);
   virtual ~DisplayMode();
+  bool operator==(const DisplayMode& other) const;

[rjkroege, 2017/02/17 03:03:51]

Why do you need this? I'd prefer that it would be unnecessary.

[thanhph1, 2017/02/21 16:52:17]

I removed this and added back a helper function in files
display_struct_traits_unittest.cc and display_snapshot_mojo_struct_traits.cc.

+  bool operator!=(const DisplayMode& other) const;
   virtual std::unique_ptr<DisplayMode> Clone() const;
 
   const gfx::Size& size() const { return size_; }
   bool is_interlaced() const { return is_interlaced_; }
   float refresh_rate() const { return refresh_rate_; }
 
   virtual std::string ToString() const;
 
  private:
   gfx::Size size_;
   bool is_interlaced_;
   float refresh_rate_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayMode);
 };
 
 // Used to by gtest to print readable errors.
 DISPLAY_TYPES_EXPORT void PrintTo(const DisplayMode& mode, std::ostream* os);
 
 }  // namespace display
 
 #endif  // UI_DISPLAY_TYPES_DISPLAY_MODE_H_