Add --timeline-recorder= flag and fix --timeline-dir flag

Add --timeline-recorder= flag and fix --timeline-dir flag

- Add --timeline-recorder= flag to allow explicit control over the recorder used.
- Fix crash when using THR_Print early in VM startup.
- Fix crash when using --timeline-dir to dump timeline to disk.

R=hausner@google.com

Committed: https://github.com/dart-lang/sdk/commit/d17214fda014161e2537b03d54ba07fee12d16e0

[Cutch, 2016-04-18 20:06:03]

Description was changed from

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

BUG=
==========

to

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

BUG=
==========

[Cutch, 2016-04-18 20:06:04]

johnmccutchan@google.com changed reviewers:
+ hausner@google.com

[Cutch, 2016-04-18 20:06:40]

Description was changed from

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

BUG=
==========

to

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

- Add --timeline-recorder= flag to allow explicit control over the recorder
used.
- Fix crash when using THR_Print early in VM startup.
- Fix crash when using --timeline-dir to dump timeline to disk.
==========

[hausner, 2016-04-18 20:24:15]

LGTM.

[Cutch, 2016-04-19 16:22:05]

Description was changed from

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

- Add --timeline-recorder= flag to allow explicit control over the recorder
used.
- Fix crash when using THR_Print early in VM startup.
- Fix crash when using --timeline-dir to dump timeline to disk.
==========

to

==========
Add --timeline-recorder= flag and fix --timeline-dir flag

- Add --timeline-recorder= flag to allow explicit control over the recorder
used.
- Fix crash when using THR_Print early in VM startup.
- Fix crash when using --timeline-dir to dump timeline to disk.

R=hausner@google.com

Committed:
https://github.com/dart-lang/sdk/commit/d17214fda014161e2537b03d54ba07fee12d16e0
==========

[Cutch, 2016-04-19 16:22:06]

Committed patchset #1 (id:1) manually as
d17214fda014161e2537b03d54ba07fee12d16e0 (presubmit successful).

[rmacnak, 2016-04-19 17:30:55]

rmacnak@google.com changed reviewers:
+ rmacnak@google.com

[rmacnak, 2016-04-19 17:30:56]

https://codereview.chromium.org/1897963002/diff/1/runtime/vm/timeline.cc
File runtime/vm/timeline.cc (left):

https://codereview.chromium.org/1897963002/diff/1/runtime/vm/timeline.cc#oldc...
runtime/vm/timeline.cc:139: } else if (FLAG_startup_timeline) {
FLAG_startup_timeline is now ignored but not removed.