REGRESSION (r138858): Crash in WebCore::FrameLoader::~FrameLoader() when opening page in a background tab
https://bugs.webkit.org/show_bug.cgi?id=109935
<rdar://problem/13225963>

Reviewed by Brady Eidson.

Previously, we were deciding if a Page could go into
the PageCache by blacklisting certain load types. Instead,
whitelist the load types that we know can go into the cache,
so that newly-added load types are not cached unless
that is explicitly desired.

The crash occurs when a page which is actively loading
is put into the page cache while doing a redirect with
FrameLoadTypeRedirectWithLockedBackForwardList (note that
this is a redirect that was not covered in the blacklist),
and then promptly removed from the page cache, resulting
in resources from the redirect target (the now-active page)
being incorrectly destroyed.

No new tests, only known crash repro case is extremely
timing dependent (and only happens in WebKit2, with tiled
drawing, in background tabs).

* history/PageCache.cpp:
(WebCore::PageCache::canCache):

Adjust a test which depended on slow-redirects going
into the page cache (which will no longer happen)
to instead click on a link.

* fast/history/timed-refresh-in-cached-frame.html:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147955 268f45cc-cd09-0410-ab3c-d52691b4dbfc