[DevTools] Postpone more agents instantiation until attached.

[DevTools] Postpone more agents instantiation until attached.

To support multiple attached devtools, we have to instantiate
individual agents on demand, rather than on creation.
This patch moves most of agents, with only worker and inspector to go.

BUG=590878
Committed: https://crrev.com/b547858514737d59af3c55b2b06b4e511624c304
Cr-Commit-Position: refs/heads/master@{#378509}

[dgozman, 2016-03-01 00:55:45]

dgozman@chromium.org changed reviewers:
+ pfeldman@chromium.org

[dgozman, 2016-03-01 00:55:46]

Take a look please.

[dgozman, 2016-03-01 01:46:03]

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

[commit-bot: I haz the power, 2016-03-01 01:46:43]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1746393003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1746393003/1

[commit-bot: I haz the power, 2016-03-01 05:19:34]

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

[commit-bot: I haz the power, 2016-03-01 05:19:35]

Dry run: This issue passed the CQ dry run.

[pfeldman, 2016-03-01 18:49:22]

lgtm

[dgozman, 2016-03-01 18:59:25]

The CQ bit was checked by dgozman@chromium.org

[commit-bot: I haz the power, 2016-03-01 19:00:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1746393003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1746393003/1

[commit-bot: I haz the power, 2016-03-01 19:16:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-01 19:18:05]

Description was changed from

==========
[DevTools] Postpone more agents instantiation until attached.

To support multiple attached devtools, we have to instantiate
individual agents on demand, rather than on creation.
This patch moves most of agents, with only worker and inspector to go.

BUG=590878
==========

to

==========
[DevTools] Postpone more agents instantiation until attached.

To support multiple attached devtools, we have to instantiate
individual agents on demand, rather than on creation.
This patch moves most of agents, with only worker and inspector to go.

BUG=590878

Committed: https://crrev.com/b547858514737d59af3c55b2b06b4e511624c304
Cr-Commit-Position: refs/heads/master@{#378509}
==========

[commit-bot: I haz the power, 2016-03-01 19:18:06]

Patchset 1 (id:??) landed as
https://crrev.com/b547858514737d59af3c55b2b06b4e511624c304
Cr-Commit-Position: refs/heads/master@{#378509}

[dgozman, 2016-03-03 19:25:54]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1761663003/ by dgozman@chromium.org.

The reason for reverting is: Speculative revert to fix performance regressions:
https://bugs.chromium.org/p/chromium/issues/detail?id=591406.