Update latest ChromeVox from upstream
Change log for this version:
Skip elements that are referenced by another element using aria-labelledby.
Override sticky mode within a single tab, rather than globally.
Don't crash if chrome.experimental doesn't exist anymore.
Basic Chrome OS touch screen support.
Handle braille text input, contracted and uncontracted.
BUG=310285
TBR=dtseng@chromium.org
Review URL: https://codereview.chromium.org/
316803004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275102 0039d316-1c4b-4281-b951-d872f2087c98