Add quic_logging

net/quic/platform/impl/quic_logging_impl.h

+// Copyright (c) 2017 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 NET_QUIC_PLATFORM_IMPL_QUIC_LOGGING_IMPL_H_
+#define NET_QUIC_PLATFORM_IMPL_QUIC_LOGGING_IMPL_H_
+
+#include "base/logging.h"
+
+#define QUIC_LOG_IMPL(severity) QUIC_DLOG(severity)
+#define QUIC_LOG_EVERY_N_SEC_IMPL(severity, seconds) QUIC_DLOG(severity)
+#define QUIC_LOG_FIRST_N_IMPL(severity, n) QUIC_DLOG(severity)

[Ryan Hamilton, 2017/01/05 15:44:55]

I'm confused by these 3 lines. api/logging.h depends on logging_imp.h but not
the other way around. So it's surprising that a definition in impl depends on
QUIC_DLOG() from api. Could this be QUIC_DLOG_IMPL(severity) instead?

+#define QUIC_DLOG_IMPL(severity) QUIC_CHROMIUM_DLOG_##severity
+#define QUIC_LOG_IF_IMPL(severity, condition) \
+  QUIC_CHROMIUM_LOG_IF_##severity(condition)
+
+#define QUIC_CHROMIUM_DLOG_INFO DVLOG(1)
+#define QUIC_CHROMIUM_DLOG_WARNING DLOG(WARNING)
+#define QUIC_CHROMIUM_DLOG_ERROR DLOG(ERROR)
+#define QUIC_CHROMIUM_DLOG_FATAL DLOG(FATAL)
+#define QUIC_CHROMIUM_DLOG_DFATAL DLOG(DFATAL)
+
+#define QUIC_CHROMIUM_LOG_IF_INFO(condition) DVLOG_IF(1, condition)
+#define QUIC_CHROMIUM_LOG_IF_WARNING(condition) DLOG_IF(WARNING, condition)
+#define QUIC_CHROMIUM_LOG_IF_ERROR(condition) DLOG_IF(ERROR, condition)
+#define QUIC_CHROMIUM_LOG_IF_FATAL(condition) DLOG_IF(FATAL, condition)
+#define QUIC_CHROMIUM_LOG_IF_DFATAL(condition) DLOG_IF(DFATAL, condition)
+
+#define QUIC_DVLOG_IMPL(verbose_level) DVLOG(verbose_level)
+
+#if defined(OS_WIN)
+// wingdi.h defines ERROR to be 0. When we call QUIC_DLOG(ERROR), it gets
+// substituted with 0, and it expands to QUIC_CHROMIUM_DLOG_0. To allow us to
+// keep using this syntax, we define this macro to do the same thing as
+// QUIC_CHROMIUM_DLOG_ERROR.
+#define QUIC_CHROMIUM_DLOG_0 QUIC_CHROMIUM_DLOG_ERROR
+#define QUIC_CHROMIUM_LOG_IF_0 QUIC_CHROMIUM_LOG_IF_ERROR
+#endif
+
+#endif  // NET_QUIC_PLATFORM_IMPL_QUIC_LOGGING_IMPL_H_