Fix two URLRequestJob subclasses that didn't support cancellation

Fix two URLRequestJob subclasses that didn't support cancellation

This was causing crashes.  I suspect there are a bunch of other
subclasses with the same issue.  :(

Also add an OWNERS file to components/about_handler.

BUG=508900, 541152
Committed: https://crrev.com/27d71098b7c60b5841a311ff3a9622f133c99319
Cr-Commit-Position: refs/heads/master@{#353271}

[mmenke, 2015-10-08 16:10:51]

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

[mmenke, 2015-10-08 16:10:52]

I think I'm going to leave the CHECKs in, for now.

[mmenke, 2015-10-08 16:16:32]

On 2015/10/08 16:10:52, mmenke wrote:
> I think I'm going to leave the CHECKs in, for now.

Not adding tests for this mostly because there are no tests specific to these
classes...and it seems silly.

Some URLREquestJob subclasses are (incorrectly) calling NotifyStartError
synchronously on start - we may want to modify URLRequestJob to actually support
that, which may at least make some things easier.

[davidben, 2015-10-08 16:16:36]

lgtm

https://codereview.chromium.org/1395643003/diff/1/components/about_handler/ur...
File components/about_handler/url_request_about_job.cc (right):

https://codereview.chromium.org/1395643003/diff/1/components/about_handler/ur...
components/about_handler/url_request_about_job.cc:35:
weak_factory_.InvalidateWeakPtrs();
Nit: Completely doesn't matter here, but I've seen both orders. My first thought
would be that InvalidateWeakPtrs() should be first, to maintain the invariant
that there is no point in time that the WeakPtr is alive and the URLRequestJob
killed. Kinda like how you destructor subclass before superclass. Thoughts?

(Ditto for the other file.)

[mmenke, 2015-10-08 16:20:42]

Thanks!

https://codereview.chromium.org/1395643003/diff/1/components/about_handler/ur...
File components/about_handler/url_request_about_job.cc (right):

https://codereview.chromium.org/1395643003/diff/1/components/about_handler/ur...
components/about_handler/url_request_about_job.cc:35:
weak_factory_.InvalidateWeakPtrs();
On 2015/10/08 16:16:36, David Benjamin wrote:
> Nit: Completely doesn't matter here, but I've seen both orders. My first
thought
> would be that InvalidateWeakPtrs() should be first, to maintain the invariant
> that there is no point in time that the WeakPtr is alive and the URLRequestJob
> killed. Kinda like how you destructor subclass before superclass. Thoughts?
> 
> (Ditto for the other file.)

Makes sense.  That also the reverse of construction order.  Done (x2).

[mmenke, 2015-10-08 16:20:56]

The CQ bit was checked by mmenke@chromium.org

[mmenke, 2015-10-08 16:20:56]

The patchset sent to the CQ was uploaded after l-g-t-m from
davidben@chromium.org
Link to the patchset: https://codereview.chromium.org/1395643003/#ps20001
(title: "Response to comments")

[commit-bot: I haz the power, 2015-10-08 16:22:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1395643003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1395643003/20001

[commit-bot: I haz the power, 2015-10-08 16:36:37]

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

[commit-bot: I haz the power, 2015-10-08 16:36:38]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[mmenke, 2015-10-08 16:48:56]

Patchset #3 (id:40001) has been deleted

[mmenke, 2015-10-08 16:51:03]

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

[mmenke, 2015-10-08 16:51:04]

[+sdefresne] as a components owner (The about_handler component didn't have any
OWNERS, which I'm also taking care of in this CL).

[sdefresne, 2015-10-09 12:12:14]

rs lgtm

[mmenke, 2015-10-09 12:14:12]

On 2015/10/09 12:12:14, sdefresne wrote:
> rs lgtm

Thanks

[mmenke, 2015-10-09 12:14:16]

The CQ bit was checked by mmenke@chromium.org

[mmenke, 2015-10-09 12:14:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
davidben@chromium.org
Link to the patchset: https://codereview.chromium.org/1395643003/#ps60001
(title: "Add OWNERS")

[commit-bot: I haz the power, 2015-10-09 12:14:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1395643003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1395643003/60001

[commit-bot: I haz the power, 2015-10-09 12:19:08]

Committed patchset #3 (id:60001)

[commit-bot: I haz the power, 2015-10-09 12:20:15]

Patchset 3 (id:??) landed as
https://crrev.com/27d71098b7c60b5841a311ff3a9622f133c99319
Cr-Commit-Position: refs/heads/master@{#353271}