Add ongoing events to net-export log when logging starts

components/net_log/net_log_file_writer.h

Index: components/net_log/net_log_file_writer.h
diff --git a/components/net_log/net_log_file_writer.h b/components/net_log/net_log_file_writer.h
index e2f3ca86347492958fb73eaba584b089efb0daa3..f095d3e5fce4c0d556a045e64a0cb51896e651e6 100644
--- a/components/net_log/net_log_file_writer.h
+++ b/components/net_log/net_log_file_writer.h
@@ -71,8 +71,9 @@ class NetLogFileWriter {
   };
 
   using FilePathCallback = base::Callback<void(const base::FilePath&)>;
-
   using DirectoryGetter = base::Callback<bool(base::FilePath*)>;
+  using URLRequestContextGetterList =
+      std::vector<scoped_refptr<net::URLRequestContextGetter>>;
 
   ~NetLogFileWriter();
 
@@ -98,7 +99,8 @@ class NetLogFileWriter {
   // empty, the default log path is used. If NetLogFileWriter is already
   // logging, this is a no-op and |capture_mode| is ignored.
   void StartNetLog(const base::FilePath& log_path,
-                   net::NetLogCaptureMode capture_mode);
+                   net::NetLogCaptureMode capture_mode,
+                   const URLRequestContextGetterList& context_getters);

[eroman, 2017/02/21 22:14:23]

Please update the comments to mention what this does. In particular can you
clarify the following:

 * These contexts are optional
 * They are ONLY used for logging the outstanding requests when logging was
first started
 * They are not used for getting the polled data
 * Why there is an asymmetry in the API (starting takes a list, whereas stopping
takes a single one)
 * All the contexts must be bound to the same thread.

 
   // Stops collecting NetLog data into the file. It is a no-op if
   // NetLogFileWriter is currently not logging.
@@ -154,6 +156,8 @@ class NetLogFileWriter {
     STATE_INITIALIZING,
     // Not currently logging to file.
     STATE_NOT_LOGGING,
+    // Currently in the process of starting the log.
+    STATE_STARTING_LOG,
     // Currently logging to file.
     STATE_LOGGING,
     // Currently in the process of stopping the log.
@@ -167,12 +171,19 @@ class NetLogFileWriter {
 
   // Called internally by Initialize(). Will initialize NetLogFileWriter's state
   // variables after the default log directory is set up and the default log
-  // path is determined.
+  // path is determined on the |file_task_runner_|.
   void SetStateAfterSetUpDefaultLogPath(
       const DefaultLogPathResults& set_up_default_log_path_results);
 
-  // Called internally by StopNetLog(). Does the actual work needed by
-  // StopNetLog() outside of retrieving the net info.
+  // Called internally by StartNetLog(). Contains tasks to be done to start
+  // logging after net log entries for ongoing events are added to the log from
+  // the |net_task_runner_|.
+  void StartNetLogAfterCreateEntriesForActiveObjects(
+      net::NetLogCaptureMode capture_mode);
+
+  // Called internally by StopNetLog(). Contains tasks to be done to stop
+  // logging after net-thread polled data is retrieved on the
+  // |net_task_runner_|.
   void StopNetLogAfterAddNetInfo(
       std::unique_ptr<base::DictionaryValue> polled_data);