[Cronet] Make StartNetLog and StopNetLog synchronous in Cronet

[Cronet] Make StartNetLog and StopNetLog synchronous in Cronet

CronetEngine.StartNetLogToFile and StopNetLog post asynchronous tasks to the
network thread. This results truncated logs if executing those tasks is slow on
the network thread. Since NetLog is a global and thread-safe, this CL creates
and tears down WriteToFileNetLogObserver on the calling Java thread. The access
to WriteToFileNetLogObserver is protected by a lock to ensure thread safety.

BUG=617632
Committed: https://crrev.com/2a0656e9ea5eac86f6dedbc9ea733c6b95b58d04
Cr-Commit-Position: refs/heads/master@{#398612}

[xunjieli, 2016-06-07 16:48:23]

xunjieli@chromium.org changed reviewers:
+ mmenke@chromium.org

[mmenke, 2016-06-08 15:33:52]

LGTM

[xunjieli, 2016-06-08 16:59:45]

The CQ bit was checked by xunjieli@chromium.org

[commit-bot: I haz the power, 2016-06-08 17:00:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2035313008/20001

[commit-bot: I haz the power, 2016-06-08 17:46:49]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-08 17:48:09]

Description was changed from

==========
[Cronet] Make StartNetLog and StopNetLog synchronous in Cronet

CronetEngine.StartNetLogToFile and StopNetLog post asynchronous tasks to the
network thread. This results truncated logs if executing those tasks is slow on
the network thread. Since NetLog is a global and thread-safe, this CL creates
and tears down WriteToFileNetLogObserver on the calling Java thread. The access
to WriteToFileNetLogObserver is protected by a lock to ensure thread safety.

BUG=617632
==========

to

==========
[Cronet] Make StartNetLog and StopNetLog synchronous in Cronet

CronetEngine.StartNetLogToFile and StopNetLog post asynchronous tasks to the
network thread. This results truncated logs if executing those tasks is slow on
the network thread. Since NetLog is a global and thread-safe, this CL creates
and tears down WriteToFileNetLogObserver on the calling Java thread. The access
to WriteToFileNetLogObserver is protected by a lock to ensure thread safety.

BUG=617632

Committed: https://crrev.com/2a0656e9ea5eac86f6dedbc9ea733c6b95b58d04
Cr-Commit-Position: refs/heads/master@{#398612}
==========

[commit-bot: I haz the power, 2016-06-08 17:48:10]

Patchset 2 (id:??) landed as
https://crrev.com/2a0656e9ea5eac86f6dedbc9ea733c6b95b58d04
Cr-Commit-Position: refs/heads/master@{#398612}