Track plugin input event latency

ppapi/cpp/private/instance_private.cc

Index: ppapi/cpp/private/instance_private.cc
diff --git a/ppapi/cpp/private/instance_private.cc b/ppapi/cpp/private/instance_private.cc
index c55408a28cbe753d32d6b269e40fea098780d82f..15e84539a1704d11db812786e52d9a4a6deed7ac 100644
--- a/ppapi/cpp/private/instance_private.cc
+++ b/ppapi/cpp/private/instance_private.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/cpp/private/instance_private.h"
 
+#include "ppapi/c/private/ppb_input_event_private.h"
 #include "ppapi/c/private/ppb_instance_private.h"
 #include "ppapi/c/private/ppp_instance_private.h"
 #include "ppapi/cpp/module_impl.h"
@@ -17,6 +18,10 @@ template <> const char* interface_name<PPB_Instance_Private>() {
   return PPB_INSTANCE_PRIVATE_INTERFACE;
 }
 
+template <> const char* interface_name<PPB_InputEvent_Private>() {
+  return PPB_INPUTEVENT_PRIVATE_INTERFACE;
+}
+
 PP_Var GetInstanceObject(PP_Instance pp_instance) {
   Module* module_singleton = Module::Get();
   if (!module_singleton)
@@ -72,4 +77,11 @@ VarPrivate InstancePrivate::ExecuteScript(const Var& script, Var* exception) {
           VarPrivate::OutException(exception).get()));
 }
 
+void InstancePrivate::StartTrackingLatency(PP_Instance instance) {
+  if (!has_interface<PPB_InputEvent_Private>())
+    return;
+  return get_interface<PPB_InputEvent_Private>()->StartTrackingLatency(
+      pp_instance());
+}
+
 }  // namespace pp