Plumbing input event latency reporting through Mus GPU.

ui/latency/latency_info.h

Index: ui/latency/latency_info.h
diff --git a/ui/latency/latency_info.h b/ui/latency/latency_info.h
index b358fbaa69a658cd4e8b71519ed305c16e1c8519..600f8745cd20e61cd800707c3a89d9a17b6e9e08 100644
--- a/ui/latency/latency_info.h
+++ b/ui/latency/latency_info.h
@@ -263,6 +263,12 @@ class 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_