Removed unregisterTerminationObserver from DatabaseContext::contextDestroyed

Removed unregisterTerminationObserver from DatabaseContext::contextDestroyed

Method DatabaseContext::contextDestroyed always calls from ExecutionContext destructor. In the case when the context is WorkerGlobalScope - from WorkerGlobalScope destructor. This unregister call does nothing in this situation.
And it looks dangerous when we try to use the methods of the object in destructor. E.g. if we make the method ExecutionContext::isWorkerGlobalScope virtual the program will crash in DatabaseContext::contextDestroyed.

R=tkent@chromium.org,vsevik@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181711

[kozyatinskiy1, 2014-09-09 12:45:35]

Hi.
Please take a look.

You added lines with unregisterTerminationObserver in
https://codereview.chromium.org/248523003

I'm working on merge ExecutionContextClient back to ExecutionContext and I need
to make ExecutionContext::isWorkerGlobalScope virtual. And after this change
executionContext()->isWorkerGlobalScope() call will crash blink. I suppose that
unregisterTerminationObserver call here is redundant.

[tkent, 2014-09-09 23:25:44]

lgtm
We can remove WorkerGlobalScope::unregisterTerminationObserver too.  There are
no other callsites.

[kozyatinskiy1, 2014-09-10 06:42:03]

On 2014/09/09 23:25:44, tkent (overloaded) wrote:
> lgtm
> We can remove WorkerGlobalScope::unregisterTerminationObserver too.  There are
> no other callsites.

Done. Thanks.

[kozyatinskiy1, 2014-09-10 06:43:34]

The CQ bit was checked by kozyatinskiy@google.com

[commit-bot: I haz the power, 2014-09-10 06:43:54]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/kozyatinskiy@google.com/551373003/20001

[commit-bot: I haz the power, 2014-09-10 08:06:46]

Committed patchset #2 (id:20001) as 181711