Plumbing input event latency reporting through Mus GPU.

ui/latency/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_LATENCY_LATENCY_INFO_H_
 #define UI_LATENCY_LATENCY_INFO_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 245 matching lines @@
   // Stores the type of the first source event.
   SourceEventType source_event_type_;
 
 #if !defined(OS_IOS)
   friend struct IPC::ParamTraits<ui::LatencyInfo>;
   friend struct mojo::StructTraits<ui::mojom::LatencyInfoDataView,
                                    ui::LatencyInfo>;
 #endif
 };
 
+// This is declared here for use in gtest-based unit tests, but is defined in
+// //ui/latency:test_support target.
+// Without this the default PrintTo template in gtest tries to pass LatencyInfo
+// by value, which leads to an alignment compile error on Windows.
+void PrintTo(const LatencyInfo& latency, ::std::ostream* os);
+
 }  // namespace ui
 
 #endif  // UI_LATENCY_LATENCY_INFO_H_