Hooks in touch fuzzing on the keyboard + unit tests.

BUG=347246,345779

Review URL: https://codereview.chromium.org/182563004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255049 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255049
Updating trunk VERSION from 1873.0 to 1874.0

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255051 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255051