Fix iframes by making an approximation of the attributes VoiceOver expects for an iframe.
The AXScrollArea role sometimes gets passed to BrowserAccessibility with a size having width == height == 0. VoiceOver apparently doesn't like this and ignores the entire subtree. This requires further investigation.
This patch also adds a missing mapping for the AXLoaded attribute.
TEST=manual.
BUG=none.
Review URL: http://codereview.chromium.org/
7482013
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@94030 0039d316-1c4b-4281-b951-d872f2087c98