Revert of Oilpan: enable appcache + move DocumentLoader to the heap.

Revert of Oilpan: enable appcache + move DocumentLoader to the heap. (patchset #11 id:190001 of https://codereview.chromium.org/1194003004/)

Reason for revert:
Linux Leak is failing on fast/html/imports/import-expando-gc.html, and this seems to be the most viable candidate for the cause.

See http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/builds/11999
and
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fast%2Fhtml%2Fimports%2Fimport-expando-gc.html&testType=layout-tests

Original issue's description:
> Oilpan: enable appcache + move DocumentLoader to the heap.
> 
> DocumentLoader belongs on the heap. References to it
> are kept by an object that is on the heap (FrameLoader),
> and DocumentLoader itself has heap references.
> 
> Along with moving DocumentLoader, have the two appcache
> objects (ApplicationCache and ApplicationCacheHost) be
> under Oilpan's control always.
> 
> R=haraken
> BUG=340522, 497595
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197576

TBR=oilpan-reviews@chromium.org,haraken@chromium.org,sigbjornf@opera.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=340522, 497595
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197585

[Stephen Chennney, 2015-06-22 17:56:49]

Created Revert of Oilpan: enable appcache + move DocumentLoader to the heap.

[commit-bot: I haz the power, 2015-06-22 17:57:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200043002/1

[commit-bot: I haz the power, 2015-06-22 17:58:30]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197585

[sof, 2015-06-22 19:05:16]

Hmm, that's one flaky test


http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fas...

[sof, 2015-06-23 12:29:24]

On 2015/06/22 19:05:16, sof wrote:
> Hmm, that's one flaky test
> 
> 
>
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fas...

Filed https://code.google.com/p/chromium/issues/detail?id=503583 (and will put
up an attempted fix to stabilize the test.)