Copy event label.

Timeline: Copy event labels of embedder events.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.

BUG=
R=johnmccutchan@google.com

Committed: https://github.com/dart-lang/sdk/commit/0555b799cd1d5cbb17eb9e3ea3fc0eddf8e4697f

[rmacnak, 2016-04-13 23:38:09]

Description was changed from

==========
Copy event label.
==========

to

==========
Timeline: Copy event labels.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.
==========

[rmacnak, 2016-04-14 01:00:54]

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

[Cutch, 2016-04-14 13:24:29]

https://codereview.chromium.org/1882313002/diff/20001/runtime/vm/timeline.cc
File runtime/vm/timeline.cc (right):

https://codereview.chromium.org/1882313002/diff/20001/runtime/vm/timeline.cc#...
runtime/vm/timeline.cc:504: label_ = strdup(label);
The timeline was designed to require const char* for the label to avoid doing
this string copy. 

Flutter should give us const char* for the labels, or, change this CL to make
copying of the label optional and only use it for events delivered via the API.

[rmacnak, 2016-04-14 23:35:15]

Description was changed from

==========
Timeline: Copy event labels.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.
==========

to

==========
Timeline: Copy event labels of embedder events.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.

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

[rmacnak, 2016-04-14 23:38:14]

with bit, PTAL

[Cutch, 2016-04-14 23:59:40]

On 2016/04/14 23:38:14, rmacnak wrote:
> with bit, PTAL

No need to change all this API. Just call set_owns_label(true) before calling
Complete. The only callers of set_owns_label will be in dart_api_impl.cc

[rmacnak, 2016-04-15 00:31:49]

Done.

[Cutch, 2016-04-15 14:00:15]

lgtm

[rmacnak, 2016-04-15 16:48:11]

Description was changed from

==========
Timeline: Copy event labels of embedder events.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.

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

to

==========
Timeline: Copy event labels of embedder events.

Fixes use-after-free of the label for the 'SkyActivity.onSkyReady' event.

BUG=
R=johnmccutchan@google.com

Committed:
https://github.com/dart-lang/sdk/commit/0555b799cd1d5cbb17eb9e3ea3fc0eddf8e4697f
==========

[rmacnak, 2016-04-15 16:48:13]

Committed patchset #4 (id:60001) manually as
0555b799cd1d5cbb17eb9e3ea3fc0eddf8e4697f (presubmit successful).