Add an explicit dispose step for WebDevToolsAgentImpl.

Add an explicit dispose step for WebDevToolsAgentImpl.

In order to provide an orderly shutdown of a WebViewImpl's
WebDevToolsAgentImpl object, add a dispose() step before clearing out
its reference. Delaying the dispose steps until WebDevToolsAgentImpl
is finalized, is incompatible with Oilpan.

R=haraken
BUG=451004
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191698

[sof, 2015-03-11 10:42:17]

sigbjornf@opera.com changed reviewers:
+ oilpan-reviews@chromium.org

[sof, 2015-03-11 10:42:17]

please take a look.

[haraken, 2015-03-11 11:00:04]

LGTM

[sof, 2015-03-11 11:04:54]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-03-11 11:05:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/996163002/1

[commit-bot: I haz the power, 2015-03-11 12:51:44]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=191698

[dgozman, 2015-03-11 15:20:44]

On 2015/03/11 12:51:44, I haz the power (commit-bot) wrote:
> Committed patchset #1 (id:1) as
> https://src.chromium.org/viewvc/blink?view=rev&revision=191698

There is already |willBeDestroyed| method on the same class. Does it suit for
your needs?

[sof, 2015-03-11 15:32:04]

On 2015/03/11 15:20:44, dgozman wrote:
> On 2015/03/11 12:51:44, I haz the power (commit-bot) wrote:
> > Committed patchset #1 (id:1) as
> > https://src.chromium.org/viewvc/blink?view=rev&revision=191698
> 
> There is already |willBeDestroyed| method on the same class. Does it suit for
> your needs?

Don't/didn't think so; that's issued first thing when closing the view; the
dispose happens after the page has been destroyed.