Write mojom and StructTraits for DisplaySnapshot.

ui/display/types/display_mode.cc

 // 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.
 
 #include "ui/display/types/display_mode.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/stringprintf.h"
 
 namespace display {
 
 DisplayMode::DisplayMode(const gfx::Size& size,
                          bool interlaced,
                          float refresh_rate)
     : size_(size),
       is_interlaced_(interlaced),
       refresh_rate_(refresh_rate) {}
 
 DisplayMode::~DisplayMode() {}
 
-std::unique_ptr<DisplayMode> DisplayMode::Clone() const {
-  return base::WrapUnique(new DisplayMode(size_,
-                                          is_interlaced_,
-                                          refresh_rate_));
+bool DisplayMode::operator==(const DisplayMode& other) const {
+  return this->size() == other.size() &&
+         this->is_interlaced() == other.is_interlaced() &&
+         this->refresh_rate() == other.refresh_rate();
+}
+
+bool DisplayMode::operator!=(const DisplayMode& other) const {
+  return !operator==(other);
 }
 
 std::string DisplayMode::ToString() const {
   return base::StringPrintf("[%dx%d %srate=%f]",
                             size_.width(),
                             size_.height(),
                             is_interlaced_ ? "interlaced " : "",
                             refresh_rate_);
 }
 
+std::unique_ptr<DisplayMode> DisplayMode::Clone() const {

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

Please keep the order consistent between header and source files. You moved
Clone() under ToString() for some reason in this patch?

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

Nice catch. Thanks!

+  return base::WrapUnique(
+      new DisplayMode(size_, is_interlaced_, refresh_rate_));
+}
+
 void PrintTo(const DisplayMode& mode, std::ostream* os) {
   *os << mode.ToString();
 }
 
 }  // namespace display