Mac Pepper: Make Image2D's TransportDIB available to the browser.
Mac Pepper: Make Image2D's TransportDIB available to the browser.

This mirrors the behaviour on other platforms, and allows the optimized Pepper
plugin painting path to be used (see RenderWidget::DoDeferredUpdate()).

BUG=none
TEST=MacFlapper paints correctly in the "windowed" case

Review URL: http://codereview.chromium.org/6359005

git-svn-id: http://src.chromium.org/svn/trunk/src@71813 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 25b6acc363b03055b0dd200605dee83e173eab4b
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser