diff --git a/ipc/chromium/src/base/message_pump_libevent.cc b/ipc/chromium/src/base/message_pump_libevent.cc
index 9ce230c..d980f9e 100644
--- a/ipc/chromium/src/base/message_pump_libevent.cc
+++ b/ipc/chromium/src/base/message_pump_libevent.cc
@@ -18,18 +18,18 @@
 #include "event.h"
 #include "mozilla/UniquePtr.h"
 
-// This macro checks that the _EVENT_SIZEOF_* constants defined in
+// This macro checks that the EVENT__SIZEOF_* constants defined in
 // ipc/chromiume/src/third_party/<platform>/event2/event-config.h are correct.
-#define CHECK_EVENT_SIZEOF(TYPE, type) \
-    static_assert(_EVENT_SIZEOF_##TYPE == sizeof(type), \
-    "bad _EVENT_SIZEOF_"#TYPE);
-
-CHECK_EVENT_SIZEOF(LONG,      long);
-CHECK_EVENT_SIZEOF(LONG_LONG, long long);
-CHECK_EVENT_SIZEOF(PTHREAD_T, pthread_t);
-CHECK_EVENT_SIZEOF(SHORT,     short);
-CHECK_EVENT_SIZEOF(SIZE_T,    size_t);
-CHECK_EVENT_SIZEOF(VOID_P,    void*);
+#define CHECKEVENT__SIZEOF(TYPE, type) \
+    static_assert(EVENT__SIZEOF_##TYPE == sizeof(type), \
+    "bad EVENT__SIZEOF_"#TYPE);
+
+CHECKEVENT__SIZEOF(LONG,      long);
+CHECKEVENT__SIZEOF(LONG_LONG, long long);
+CHECKEVENT__SIZEOF(PTHREAD_T, pthread_t);
+CHECKEVENT__SIZEOF(SHORT,     short);
+CHECKEVENT__SIZEOF(SIZE_T,    size_t);
+CHECKEVENT__SIZEOF(VOID_P,    void*);
 
 // Lifecycle of struct event
 // Libevent uses two main data structures: