Implement LatencyInfo StructTraits

ui/events/latency_info.h

 // Copyright 2013 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_EVENTS_LATENCY_INFO_H_
 #define UI_EVENTS_LATENCY_INFO_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/containers/small_map.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/events/events_base_export.h"
 
 #if !defined(OS_IOS)
 #include "ipc/ipc_param_traits.h"  // nogncheck
+#include "mojo/public/cpp/bindings/struct_traits.h"  // nogncheck
 #endif
 
 namespace ui {
 
+#if !defined(OS_IOS)
+namespace mojom {
+class LatencyInfo;
+}
+#endif
+
 // When adding new components, or new metrics based on LatencyInfo,
 // please update latency_info.dot.
 enum LatencyComponentType {
   // ---------------------------BEGIN COMPONENT-------------------------------
   // BEGIN COMPONENT is when we show the latency begin in chrome://tracing.
   // Timestamp when the input event is sent from RenderWidgetHost to renderer.
   INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
   // In threaded scrolling, main thread scroll listener update is async to
   // scroll processing in impl thread. This is the timestamp when we consider
   // the main thread scroll listener update is begun.
@@ skipping 86 matching lines @@
     InputCoordinate();
     InputCoordinate(float x, float y);
 
     float x;
     float y;
   };
 
   // Empirically determined constant based on a typical scroll sequence.
   enum { kTypicalMaxComponentsPerLatencyInfo = 10 };
 
-  enum { kMaxInputCoordinates = 2 };
+  enum : size_t { kMaxInputCoordinates = 2 };
 
   // Map a Latency Component (with a component-specific int64_t id) to a
   // component info.
   typedef base::SmallMap<
       std::map<std::pair<LatencyComponentType, int64_t>, LatencyComponent>,
       kTypicalMaxComponentsPerLatencyInfo> LatencyMap;
 
   LatencyInfo();
   LatencyInfo(const LatencyInfo& other);
   ~LatencyInfo();
@@ skipping 90 matching lines @@
 
   // The unique id for matching the ASYNC_BEGIN/END trace event.
   int64_t trace_id_;
   // Whether this event has been coalesced into another event.
   bool coalesced_;
   // Whether a terminal component has been added.
   bool terminated_;
 
 #if !defined(OS_IOS)
   friend struct IPC::ParamTraits<ui::LatencyInfo>;
+  friend struct mojo::StructTraits<ui::mojom::LatencyInfo, ui::LatencyInfo>;
 #endif
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_LATENCY_INFO_H_