Revert of Fix crash which occurs when a widget destroys itself as a result of ET_GESTURE_TAP_DOWN  (https://codereview.chromium.org/169443005/)

Reason for revert:
Breaks ChromiumOS ASAN: http://build.chromium.org/p/chromium.memory/builders/Linux%20Chromium%20OS%20ASAN%20Tests%20%281%29/builds/15949




Original issue's description:
> Fix crash which occurs when a widget destroys itself as a result of ET_GESTURE_TAP_DOWN 
> 
> BUG=342867
> TEST=WidgetTest.WidgetDeleted_InDispatchGestureEvent
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=252214

TBR=sadrul@chromium.org,pkotwicz@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=342867

Review URL: https://codereview.chromium.org/173863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252235 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252235