Define HTTP2_FLAG_COUNT and use it for http2_varint_decode_64_bits.

This CL lands server change 221616382 by bnc.

BUG=488484

Change-Id: I2f8d913b85d57a565da11572e8dc87b6c3a6495b
Reviewed-on: https://chromium-review.googlesource.com/c/1341092Reviewed-by: Dianna Hu <diannahu@chromium.org>
Commit-Queue: Ryan Hamilton <rch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611350}

net/BUILD.gn

@@ -1209,6 +1209,7 @@ component("net") {
       "third_party/http2/http2_structures.h",
       "third_party/http2/platform/api/http2_arraysize.h",
       "third_party/http2/platform/api/http2_export.h",
+      "third_party/http2/platform/api/http2_flag_utils.h",
       "third_party/http2/platform/api/http2_flags.h",
       "third_party/http2/platform/api/http2_optional.h",
       "third_party/http2/platform/api/http2_ptr_util.h",
@@ -1218,6 +1219,7 @@ component("net") {
       "third_party/http2/platform/api/http2_string_utils.h",
       "third_party/http2/platform/impl/http2_arraysize_impl.h",
       "third_party/http2/platform/impl/http2_export_impl.h",
+      "third_party/http2/platform/impl/http2_flag_utils_impl.h",
       "third_party/http2/platform/impl/http2_flags_impl.cc",
       "third_party/http2/platform/impl/http2_flags_impl.h",
       "third_party/http2/platform/impl/http2_optional_impl.h",

net/third_party/http2/hpack/varint/hpack_varint_decoder.cc

@@ -4,6 +4,7 @@
 
 #include "net/third_party/http2/hpack/varint/hpack_varint_decoder.h"
 
+#include "net/third_party/http2/platform/api/http2_flag_utils.h"
 #include "net/third_party/http2/platform/api/http2_string_utils.h"
 
 namespace http2 {
@@ -43,6 +44,7 @@ DecodeStatus HpackVarintDecoder::StartExtended(uint8_t prefix_length,
 
 DecodeStatus HpackVarintDecoder::Resume(DecodeBuffer* db) {
   if (decode_64_bits_) {
+    HTTP2_FLAG_COUNT(chromium_flag_http2_varint_decode_64_bits);
     // There can be at most 10 continuation bytes.  Offset is zero for the
     // first one and increases by 7 for each subsequent one.
     const uint8_t kMaxOffset = 63;

net/third_party/http2/platform/api/http2_flag_utils.h

+// Copyright 2018 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_THIRD_PARTY_HTTP2_PLATFORM_API_HTTP2_FLAG_UTILS_H_
+#define NET_THIRD_PARTY_HTTP2_PLATFORM_API_HTTP2_FLAG_UTILS_H_
+
+#include "net/third_party/http2/platform/impl/http2_flag_utils_impl.h"
+
+#define HTTP2_FLAG_COUNT HTTP2_FLAG_COUNT_IMPL
+#define HTTP2_FLAG_COUNT_N HTTP2_FLAG_COUNT_N_IMPL
+
+#define HTTP2_CODE_COUNT HTTP2_CODE_COUNT_IMPL
+#define HTTP2_CODE_COUNT_N HTTP2_CODE_COUNT_N_IMPL
+
+#endif  // NET_THIRD_PARTY_HTTP2_PLATFORM_API_HTTP2_FLAG_UTILS_H_

net/third_party/http2/platform/impl/http2_flag_utils_impl.h

+// Copyright 2018 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_THIRD_PARTY_HTTP2_PLATFORM_IMPL_HTTP2_FLAG_UTILS_IMPL_H_
+#define NET_THIRD_PARTY_HTTP2_PLATFORM_IMPL_HTTP2_FLAG_UTILS_IMPL_H_
+
+#include "base/logging.h"
+
+#define HTTP2_FLAG_COUNT_IMPL(flag) \
+  DVLOG(1) << "FLAG_" #flag ": " << FLAGS_##flag
+#define HTTP2_FLAG_COUNT_N_IMPL(flag, instance, total) \
+  HTTP2_FLAG_COUNT_IMPL(flag)
+
+#define HTTP2_CODE_COUNT_IMPL(name) \
+  do {                              \
+  } while (0)
+#define HTTP2_CODE_COUNT_N_IMPL(name, instance, total) \
+  do {                                                 \
+  } while (0)
+
+#endif  // NET_THIRD_PARTY_HTTP2_PLATFORM_IMPL_HTTP2_FLAG_UTILS_IMPL_H_