Have FrameFetchContext check for frame detached status more often.

Have FrameFetchContext check for frame detached status more often.

Following r191022, a ResourceFetcher will no longer switch to a null
FetchContext upon it entering a frame-detached state, but continue to
call upon its FrameFetchContext in that state.

The latter wasn't fully prepared for being used in such a frame-less state,
so add the required checks.

R=mkwst@chromium.org
BUG=458222
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191045

[sof, 2015-02-28 20:08:53]

sigbjornf@opera.com changed reviewers:
+ japhet@chromium.org, mkwst@chromium.org

[sof, 2015-02-28 20:08:53]

Please take a look.

Crash(es) can be seen on trunk, 


https://storage.googleapis.com/chromium-layout-test-archives/WebKit_Win7__dbg...

A blunt looking change to FrameFetchContext, but the frame-detached state needs
to be handled by some party now that ResourceFetcher no longer relies on
FetchContext::nullInstance (and it cannot readily again either.)

[Mike West, 2015-02-28 20:54:57]

LGTM, thanks for the blunt-but-effective fix! :)

[Mike West, 2015-02-28 20:56:33]

On 2015/02/28 at 20:54:57, Mike West wrote:
> LGTM, thanks for the blunt-but-effective fix! :)

(though the linux_blink_rel bot seems to be crashing with the fix, which doesn't
make a ton of sense)

[sof, 2015-02-28 22:12:29]

On 2015/02/28 20:56:33, Mike West wrote:
> On 2015/02/28 at 20:54:57, Mike West wrote:
> > LGTM, thanks for the blunt-but-effective fix! :)
> 
> (though the linux_blink_rel bot seems to be crashing with the fix, which
doesn't
> make a ton of sense)

thanks, both the rel and dbg linux builders are prone to meltdowns today, but
quite sure it is unrelated.

[sof, 2015-02-28 22:16:58]

Will try to land this now, but if japhet has plans on how to address frame
detachment & better, feel free to undo/revert.

[sof, 2015-02-28 22:17:38]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-02-28 22:18:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/967893002/1

[commit-bot: I haz the power, 2015-03-01 00:53:46]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=191045