Unreviewed, rolling out r112954 and r112969.

Unreviewed, rolling out r112954 and r112969.
http://trac.webkit.org/changeset/112954
http://trac.webkit.org/changeset/112969
https://bugs.webkit.org/show_bug.cgi?id=79172

Hits "ASSERTION FAILED: !m_isHandlingDrag" in DnD-related
tests on Debug bots

Source/WebCore:

* page/DragController.cpp:
(WebCore::DragController::performDrag):

LayoutTests:

* fast/events/drag-dataTransferItemList.html:
* fast/events/drop-handler-should-not-stop-navigate-expected.txt: Removed.
* fast/events/drop-handler-should-not-stop-navigate.html: Removed.
* http/tests/security/clipboard/clipboard-file-access.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@113004 268f45cc-cd09-0410-ab3c-d52691b4dbfc