fixup! [M48_2564] Chromium upversion to m48_2564 branch
RenderViewHost was separated from RenderWidgetHost after [1].
So we need to get RWHI from RVHI by |GetWidget()| to access
RWHI's member functions.
[1] https://codereview.chromium.org/
1413643002
Bug: http://web.sec.samsung.net/bugzilla/show_bug.cgi?id=15384
Bug: http://web.sec.samsung.net/bugzilla/show_bug.cgi?id=15385
Reviewed by: a1.gomes, sns.park
Change-Id: I51b483144524172ffb428db180d94ffc162d5eec
Signed-off-by: SangHyup Lee <sh53.lee@samsung.com>