tracing: remove WatchEvent feature

tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

BUG=

Committed: https://crrev.com/698739dd57e2ae2c5b6a985840dc389a6dc8e18f
Cr-Commit-Position: refs/heads/master@{#426233}

[Primiano Tucci (use gerrit), 2016-10-19 15:36:50]

The CQ bit was checked by primiano@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-19 15:37:21]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Primiano Tucci (use gerrit), 2016-10-19 16:49:47]

Description was changed from

==========
tracing: get rid of WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace buffer.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

to

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace buffer.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

[Primiano Tucci (use gerrit), 2016-10-19 16:49:47]

primiano@chromium.org changed reviewers:
+ nasko@chromium.org, oysteine@chromium.org

[Primiano Tucci (use gerrit), 2016-10-19 16:52:25]

primiano@chromium.org changed reviewers:
+ dcheng@chromium.org
- nasko@chromium.org

[Primiano Tucci (use gerrit), 2016-10-19 16:52:25]

oysteine: I like to maintain unused features, but not on Wednesdays

dcheng: need SECURITY_OWNERS stamp for removing 3 IPCS in tracing_messages.h

[dcheng, 2016-10-19 17:06:13]

ipc lgtm

[commit-bot: I haz the power, 2016-10-19 17:14:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-19 17:14:17]

Dry run: This issue passed the CQ dry run.

[oystein (OOO til 10th of July), 2016-10-19 17:14:49]

Happiness is a dead foot-gun.

lgtm!

[Primiano Tucci (use gerrit), 2016-10-19 17:15:31]

Description was changed from

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace buffer.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

to

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

[nasko, 2016-10-19 17:21:38]

nasko@chromium.org changed reviewers:
+ nasko@chromium.org

[nasko, 2016-10-19 17:21:38]

Code removal always LGTM :).

[Primiano Tucci (use gerrit), 2016-10-19 17:22:42]

Allright, thanks folks. landing at the sound of:

"you don't watch trace events. trace events watch you"

[Primiano Tucci (use gerrit), 2016-10-19 17:22:48]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2016-10-19 17:23:29]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-19 17:28:26]

Description was changed from

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

to

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

[commit-bot: I haz the power, 2016-10-19 17:28:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-21 13:09:47]

Description was changed from

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

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

to

==========
tracing: remove WatchEvent feature

Long time ago WatchEvent introduced the ability to get callbacks for
trace events. This was used by the first versions of the devtools
timeline before it was able to consume the actual trace JSON.
This feature is now unused. Removing it as it causes unnecessary
maintainance burden and is a very dangerous footgun, which allows
a random client to screw up the performance characteristics of tracing.

BUG=

Committed: https://crrev.com/698739dd57e2ae2c5b6a985840dc389a6dc8e18f
Cr-Commit-Position: refs/heads/master@{#426233}
==========

[commit-bot: I haz the power, 2016-10-21 13:09:49]

Patchset 1 (id:??) landed as
https://crrev.com/698739dd57e2ae2c5b6a985840dc389a6dc8e18f
Cr-Commit-Position: refs/heads/master@{#426233}