Unreviewed rollout of r154571. Broke internal iOS build.

Reopened: No need for clearTimers function in Frame
https://bugs.webkit.org/show_bug.cgi?id=120265

* history/CachedFrame.cpp:
(WebCore::CachedFrame::CachedFrame):
(WebCore::CachedFrame::destroy):
* page/Frame.cpp:
(WebCore::Frame::clearTimers):
* page/Frame.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154577 268f45cc-cd09-0410-ab3c-d52691b4dbfc