Fix about:flags information not showing up in chrome://net-export/ logs

components/net_log/chrome_net_log.cc

 // Copyright (c) 2012 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.
 
 #include "components/net_log/chrome_net_log.h"
 
 #include <stdio.h>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 11 matching lines @@
 #include "net/log/trace_net_log_observer.h"
 #include "net/log/write_to_file_net_log_observer.h"
 
 namespace net_log {
 
 ChromeNetLog::ChromeNetLog(
     const base::FilePath& log_file,
     net::NetLogCaptureMode log_file_mode,
     const base::CommandLine::StringType& command_line_string,
     const std::string& channel_string)
-    : net_log_file_writer_(
-          new NetLogFileWriter(this, command_line_string, channel_string)) {
+    : net_log_file_writer_(new NetLogFileWriter(this)) {
   if (!log_file.empty()) {
     // Much like logging.h, bypass threading restrictions by using fopen
     // directly.  Have to write on a thread that's shutdown to handle events on
     // shutdown properly, and posting events to another thread as they occur
     // would result in an unbounded buffer size, so not much can be gained by
     // doing this on another thread.  It's only used when debugging Chrome, so
     // performance is not a big concern.
     base::ScopedFILE file;
 #if defined(OS_WIN)
     file.reset(_wfopen(log_file.value().c_str(), L"w"));
 #elif defined(OS_POSIX)
     file.reset(fopen(log_file.value().c_str(), "w"));
 #endif
 
     if (!file) {
       LOG(ERROR) << "Could not open file " << log_file.value()
                  << " for net logging";
     } else {
       std::unique_ptr<base::Value> constants(
           GetConstants(command_line_string, channel_string));

[davidben, 2017/06/30 18:03:26]

This bit means we still won't capture about:flags if you use --log-net-log,
right? (Dunno how much we care about that.)

[eroman, 2017/06/30 18:24:37]

Correct.
--log-net-log needs some more loving, before it is worth tackling this.

The way I expect this should be sequenced is:

(1) Make --log-net-log use the same code for writing logs as net-export
(https://bugs.chromium.org/p/chromium/issues/detail?id=716570). It is not
feasible to improve things when we have so many variants of log writing. At
least the net-internals version is dead now, but still some left to kill.

(2) Switch the underlying file logging mechanism to support truncation
(https://bugs.chromium.org/p/chromium/issues/detail?id=679030). Should complete
the interns work and enable the bounded logger.

(3) Further change the log format to make things not suck. #profit.
 * Choices like requiring naming all enums complicates things like
https://bugs.chromium.org/p/chromium/issues/detail?id=90674
  * Compress and/or use a binary format instead of the terrible JSON -
https://bugs.chromium.org/p/chromium/issues/detail?id=132160

       write_to_file_observer_.reset(new net::WriteToFileNetLogObserver());
 
       write_to_file_observer_->set_capture_mode(log_file_mode);
 
       write_to_file_observer_->StartObserving(this, std::move(file),
                                               constants.get(), nullptr);
     }
   }
 
   trace_net_log_observer_.reset(new net::TraceNetLogObserver());
   trace_net_log_observer_->WatchForTraceStart(this);
 }
 
 ChromeNetLog::~ChromeNetLog() {
   net_log_file_writer_.reset();
   // Remove the observers we own before we're destroyed.
   if (write_to_file_observer_)
     write_to_file_observer_->StopObserving(nullptr);
   if (trace_net_log_observer_)
     trace_net_log_observer_->StopWatchForTraceStart();
 }
 
+NetLogFileWriter* ChromeNetLog::net_log_file_writer() {
+  if (!net_log_file_writer_)
+    net_log_file_writer_ = base::WrapUnique(new NetLogFileWriter(this));
+  return net_log_file_writer_.get();
+}
+
 // static
 std::unique_ptr<base::Value> ChromeNetLog::GetConstants(
     const base::CommandLine::StringType& command_line_string,
     const std::string& channel_string) {
   std::unique_ptr<base::DictionaryValue> constants_dict =
       net::GetNetConstants();
   DCHECK(constants_dict);
 
   // Add a dictionary with the version of the client and its command line
   // arguments.
@@ skipping 15 matching lines @@
 
   constants_dict->Set("clientInfo", std::move(dict));
 
   data_reduction_proxy::DataReductionProxyEventStore::AddConstants(
       constants_dict.get());
 
   return std::move(constants_dict);
 }
 
 }  // namespace net_log