Fix crash which occurs when a widget destroys itself as a result of ET_GESTURE_TAP_DOWN 

BUG=342867
TEST=WidgetTest.WidgetDeleted_InDispatchGestureEvent
TBR=sadrul

Review URL: https://codereview.chromium.org/180803006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253962 0039d316-1c4b-4281-b951-d872f2087c98
Fixes entering upper case bug and adds unit tests.

BUG=347648

Review URL: https://codereview.chromium.org/183803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253963 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253963