Reland "Block internal PlatformEvents before they are dispatched in touchview."
Using KeyboardCodeFromXKeyEvent instead to avoid dependency on events from events_base. Previous attempt review here: https://codereview.chromium.org/
313913004/
TBR=sadrul
BUG=374002, 368669
TEST=EventsXTest.Disable*
TEST=On device opened past 180 degrees, hold shift and click on link. Link
should open in same window.
Review URL: https://codereview.chromium.org/
351083002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@279922 0039d316-1c4b-4281-b951-d872f2087c98